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==Gradient of scalar field dotted with vector field ==

Just a thought, why is this notation:

:{{bigmath|(∇''f'' )⋅ '''v'''}}

not recommended? There is nothing controversial about it... [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 12:54, 3 February 2013 (UTC)
: Of course, I expressed the thought poorly. In an article, where nothing but vector fields and gradients is needed, it may be used. But if we have to operate with both vectors and higher tensors, then the use of different styles for tensor fields of different types would be confusing. [[User:Incnis Mrsi|Incnis Mrsi]] ([[User talk:Incnis Mrsi|talk]]) 13:46, 3 February 2013 (UTC)

::Makes sense, thanks, [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 13:51, 3 February 2013 (UTC)
:: I restricted the example to settings with an indeterminate metric tensor. [[User:Incnis Mrsi|Incnis Mrsi]] ([[User talk:Incnis Mrsi|talk]]) 15:25, 3 February 2013 (UTC)

== F<sub>external</sub> ==
Why not to merge it to already existing “If an item which obeys different typographical rules has to be included” paragraph? [[User:Incnis Mrsi|Incnis Mrsi]] ([[User talk:Incnis Mrsi|talk]]) 15:25, 3 February 2013 (UTC)

:Ok, will do. Just thought to place it in contrast with the tensor notation. [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 15:32, 3 February 2013 (UTC)
:: Why it was not get into the table? [[User:Incnis Mrsi|Incnis Mrsi]] ([[User talk:Incnis Mrsi|talk]]) 16:07, 3 February 2013 (UTC)
:::Done. [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 17:24, 3 February 2013 (UTC)

==Table format for introduction examples?==

Why? A table should present information which can be correlated into rows and columns, these are just random examples. All that's needed are simple lists, like so: 

;[[#Units and quantities|Units and quantities]]

*The [[speed of light]]: {{mvar|''c''}}&nbsp;=&nbsp;{{val|299792458|u=m·s<sup>−1</sup>}},
*[[Planck's constant]]: {{mvar|''ħ''}}&nbsp;=&nbsp;{{val|1.054571726|(47)|e=-34|u=J·s}},
*[[Coulomb's constant]]: {{math|{{sfrac|1|4π''ε''<sub>0</sub>}}}}&nbsp;=&nbsp;{{val|8.987551787368|e=9|u=N·m<sup>2</sup>·C<sup>−2</sup>}}.

;[[#Common mathematical formulae|Common mathematical formulae]]

*[[Newton's second law]]: displayed,
::{{bigmath|'''F''' {{=}} {{sfrac|''d'''''p'''|''dt''}}}} 
:or inline for simpler special case, {{math|1 ='''F''' {{=}} ''m'''''a'''}}.
*[[Schrödinger equation]]: displayed (see [[#Common mathematical formulae|below]] for angular brackets),
::{{bigmath|''iħ''{{sfrac|''d''|''dt''}}{{!}}Ψ{{rangle}} {{=}} ''Ĥ''{{!}}Ψ{{rangle}}}} 
:or inline, {{math|''iħ''{{sfrac|∂Ψ|∂''t''}} {{=}} ''Ĥ''Ψ}}.
*The non-homogenous [[continuity equation]]: displayed,
::{{bigmath|{{sfrac|''∂ρ''|''∂t''}} + ∇·'''j''' {{=}} ''σ''}} 
:or inline for simpler form, {{math|''∂<sub>α</sub>J<sup>α</sup>'' {{=}} ''σ''}} (see [[#Common mathematical formulae|below]] for tensor indices).

;[[#Substances and reactions|Substances and reactions]]

*[[Electron–positron annihilation]]: inline, {{Subatomic particle|Electron}} + {{Subatomic particle|Positron}} → 2{{Subatomic particle|Photon}}.
*Example of [[beta decay|β<sup>−</sup>&nbsp;decay]]: displayed,
::{{ComplexNuclide2|americium|242|charge=5+}} → {{ComplexNuclide2|curium|242|charge=6+}} + {{Subatomic particle|Electron}} + {{Subatomic particle|Electron Antineutrino}}
*[[Particle physics|Particle]] reaction of above [[Radioactive decay|nuclear decay]]: displayed,
::[[neutron|n]]<sup>0</sup> → [[proton|p]]<sup>+</sup> + {{Subatomic particle|Electron}} + {{Subatomic particle|Electron Antineutrino}}
:or in terms of [[quark]]s, displayed again,
::([[up quark|u]][[down quark|d]]d) → (uud) + {{Subatomic particle|Electron}} + {{Subatomic particle|Electron Antineutrino}}

any better or worse? At the same time, it shows what the inline/displayed formats of the {{tl|math}} template look like... [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 15:32, 3 February 2013 (UTC)
: In my initial version the table [[Special:PermanentLink/536342940#Introduction|was not stuffed]] with extra-wide examples, and was not split to 3 rows of unclear purpose&nbsp;– there was only one content row (but more that 1 example per cell). Of course, the present table is awful and the list would be better, if you will not be extremely verbose in Introduction. [[User:Incnis Mrsi|Incnis Mrsi]] ([[User talk:Incnis Mrsi|talk]]) 16:07, 3 February 2013 (UTC)

::I know it wasn't stuffed before I did so, I presumed when you wrote "more examples, please" to add more content in rows, not within the same cells, apologies for that. Also I did originally plan to link "p for proton" as [[proton|p]] in the actual reaction, but then decided not to for consistency with the other reactions you wrote that had no links... (and the "verbosity" is not intensional, it happens during an explaination...)[[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 17:24, 3 February 2013 (UTC)

:::I think it would be better to integrate those examples in their respective subsections. Where they are now they only serve to clarify what we mean by the subsection headings, which we could achieve by one short example each, but even that I don't think is needed. Good work otherwise! &mdash;&thinsp;[[User:Hhhippo|<span style="color:darkblue; font-family:times;">'''H<small>HHIPPO</small>'''</span>]] 22:28, 3 February 2013 (UTC)

::::Yes I thought that too, but see the link provided by Incnis Mrsi above: [[Special:PermanentLink/536342940#Introduction|was not stuffed]], where he requested more examples there and then. [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 23:01, 3 February 2013 (UTC)

== Ratio of infinitesimals or derivative? ==

Would it be worth adding this subsubsubsection:

---------------------------------

;Ratios of [[differential (infinitesimal)]] quantities and [[derivative]]s

{{see also|Notation for differentiation}}
In physics, ratios of [[differential (infinitesimal)]] quantities frequently occur, and share the same notation with first order [[derivative]]s, which also frequently occur. For example, the differential amount of [[work (physics)|work]] {{math|''dW''}} done by a [[force]] {{math|'''F'''}} to move a particle over an infinitesimal displacement {{math|''d'''''r'''}} is:

:{{bigmath|''dW'' {{=}} '''F''' ∙ ''d'''''r'''}}

then dividing by an infinitesimal time increment {{math|''dt''}} gives the rate of doing work, the [[power (physics)|power]];

:{{bigmath|{{sfrac|''dW''|''dt''}} {{=}} '''F''' ∙ {{sfrac|''d'''''r'''|''dt''}} → ''P'' {{=}} '''F''' ∙ '''v'''}}

where 

:{{bigmath|'''v''' {{=}} {{sfrac|''d'''''r'''|''dt''}}}}

is the velocity of the moving particle.

Notations can be misleading, as 
*the derivative is defined as a [[Limit (mathematics)|limit]]ing [[difference quotient]], but also an [[operator]] (cf [[linear algebra]]), 
*calculating the [[differential of a function]] is a general way to determine infinitesimal changes of a quantity using a derivative.

So these are not exactly the same, differentials are more general. Following are the recommended applications of the notation.

:{| class="wikitable"
|-
! Operations 
! Notation
! Usage in the literature
|-
| Division of infinitesimal quantities {{math|''dy''}} and {{math|''dx''}}
| {{bigmath|{{sfrac|''dy''|''dx''}}, {{frac|''dy''|''dx''}}, ''dy''/''dx''}}
| 
Ratios or derivatives
|-
| Derivative of {{math|''y'' {{=}} ''y''(''x'')}} as a [[function (mathematics)|function]] of {{math|''x''}}
| {{bigmath|{{sfrac|''d''|''dx''}}''y''}}
| 
* Used only for derivatives, not ratios as above,
* makes clear that differentiation is an operator,
* clarifies notation for higher derivatives by repeated action of a derivative,
::{{bigmath|{{sfrac|''d<sup>n</sup>''|''dx<sup>n</sup>''}} {{=}} {{sfrac|''d''|''dx''}}...{{sfrac|''d''|''dx''}}{{sfrac|''d''|''dx''}}''y''}}
|-
|}

For partial derivatives this is not a problem, since differentials are never written as "{{math|''∂x''}}"; only the full symbol of a partial derivative, in any of the equivalent notations;

:{{bigmath|{{sfrac|''∂F''|''∂x''}}, {{sfrac|''∂''|''∂x''}}''F'', {{frac|''∂F''|''∂x''}}, {{frac|''∂''|''∂x''}}''F'', ''∂F''/''∂x'', }}

has meaning.

---------------------------------

to [[Wikipedia:MOSPHYS#Nomenclature and notation|Nomenclature and notation]], or [[Wikipedia:MOSPHYS#Mathematics|Mathematics]], or where? I think we should agree on this concept throughout physics articles... It's tripped me up before... I don't see this in [[WP:MOSMATH]] either... [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 09:00, 5 February 2013 (UTC)
: It should be explained in a dedicated subsection in #Nomenclature_and_notation (possibly explaining that the differential of the scalar function is an [[1-form]]) and to be mentioned in the table in #Mathematics too. But just a quibble: use {{unichar|2219|bullet operator}} for dot product, and never use U+2022 for it. <small>Also, I think that any display formula which contains a [[vinculum (symbol)|vinculum]] has to be formatted in &lt;math> unless there is a solid substantiation to do otherwise.</small> [[User:Incnis Mrsi|Incnis Mrsi]] ([[User talk:Incnis Mrsi|talk]]) 10:07, 5 February 2013 (UTC)

::Ok. For the dot product I just use the small dot symbol in the "symbols" of the "special characters" in the edit window, but wil change to {{unichar|2219|bullet operator}}. Are you sure about changing all fractions, roots, and derivatives, each with a vinculum, from {{tl|math}} to <nowiki><math></nowiki> ? [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 10:40, 5 February 2013 (UTC)

==Edits in 26–28 February==

As is usually the case, I have spent [http://en.wikipedia.org/enwiki/w/index.php?title=Wikipedia:MOSPHYS&action=history an excessive number of edits] trying to improve, but there are still a number of loose ends:

*I added another section to what this page calls "formulae"; notation for [[Wikipedia:MOSPHYS#sets and spaces|sets and spaces]], which seems to be appropriate, since "units" and their symbols are in this categorization...
*What font should be used for tensors when not written in index notation? [[Wikipedia:MOSPHYS#Vectors and vector spaces|See here]].
*What font to use for standard number sets, like for integers/real/complex etc. numbers? [[Wikipedia:MOSPHYS#Sets and spaces|See here]]. Blackboard bold is fine in LaTeX but ''not'' ideal for wikicode, as we have to keep copying and pasting the characters from somewhere else... Same for calligraphic/script letters...
*<s>Does everyone agree that '''''fraktur is extremely nasty to use'''''? Most likely not. Unfortunately ''it is'' used for real/imaginary axes in the complex plane, and for denoting groups in group theory, and elsewhere... The point is - it looks '''extremely horrible''', it is '''unreadable''', and is '''hell to write down by hand'''... And what ''millenuim'' do we live in anyway?? The [[middle ages]] are in the dim and distant past... >_< 
:Other (''readable!'') fonts can easily suffice...</s> I have no doubt other editors like to use it though, and can live with that case... 
*In general do we agree on the use of sans serif? Apparently there has been debate of it's use on WP, [[Help talk:Displaying a formula/Archive 2#\mathsf (sans serif)|See here]]...
*What about typography of Greek letters? Their application for [[WP:MOSPHYS#Subscripts and superscripts|indices is included]], but what about when they're just used like any variable; say a [[wavefunction]] {{math|ψ, ''ψ''}}, or an angle {{math|θ, ''θ''}}? I think it's silly that lower case Greek isn't always italicized (look around WP physics and maths pages...)... Apart from tensor indices, ''why'' treat Greek and Latin alphabets different? We should just use {{math|''ψ''}} in exactly the same way as for {{math|''x''}}. This is ''partial'' though, since capital Greek looks ''slightly'' odd (IMO): {{math|''Φ, Ψ, Ω''}}... compare to {{math|''P'', ''J'', ''Y''}}...
*The [[Wikipedia:MOSPHYS#mathematics|prerequisite knowledge for the mathematics]] section needs completion, the classification of difficulty could use better naming (to be less "educational"..) and the now-called [[Wikipedia:MOSPHYS#graduate level|"graduate level"]] section could potentially be too long, so just reduce that to a descriptive paragraph? Ok, [[Wikipedia talk:WikiProject Mathematics#List of well-known mathematical operations|wikiproject maths]] has already been asked about what operations (and formalism?) is well-known... and some of the discussion has been incorporated into my recent editing, but again it's still incomplete...
*Are there any more opinions on [[Wikipedia:MOSPHYS#Sidebar and navbox templates|sidebars/navboxes]] than those currently included? [[Wikipedia talk:WikiProject Physics#Picture proposal for template:classical mechanics|See here]] and [[Wikipedia talk:WikiProject Physics#Form/structure/application of Template:Tensors|here]].

These are things we need '''agreement''' on. Of course, any feedback will help (apart from how irregular the mathematical typesetting alternates between LaTeX and wikicode... which has already by raised). Thanks, [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 19:59, 27 February 2013 (UTC)
: I opt for use of 
:: <math>\mathfrak{su}(n)</math>
: in display style, but for '''su'''(''n'') inline. Greek lowercase letters pose an interesting question. Its solution depends on whether Roman Greek lowercase letters are available in &lt;math> and, more precisely, in both of its major presentations. [[User:Incnis Mrsi|Incnis Mrsi]] ([[User talk:Incnis Mrsi|talk]]) 19:29, 28 February 2013 (UTC)
::Sorry - didn't realize this post just now either... Italic greek are possible in {{tl|math}} and LaTeX, yet upright Greek letters are easily possible in {{tl|math}}, but not at all in LaTeX... That's actually a reason to ''favour'' italic lowercase Greek letters though. [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 20:39, 28 February 2013 (UTC)
:Forgot to add: hats or no hats for operators? (Although my preference is irrelevant - hats are preferable). [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 19:10, 28 February 2013 (UTC)

== Needs streamlining ==

I'm impressed by the amount of effort that has gone into developing this manual of style. Kudos to Incnis Mrsi and Maschen! However, there is a lot of material that duplicates other style guides, making it hard to determine where the physics guidelines differ. The more concise it is, the easier it will be to use. For example, section 1.2.1 (on markup) isn't needed here. Also, I don't see why such an extensive discussion of elementary operations is needed. [[User:RockMagnetist|RockMagnetist]] ([[User talk:RockMagnetist|talk]]) 05:19, 28 February 2013 (UTC)

:The operations section can be shortend, but a section on this theme is definitely needed (so when writing articles we can agree on what to expect from the reader).
:Maybe we could try to amplify the scope of those sections while keeping a compact table format: for instance while outlining prerequisites, we actually do include notational conventions (which would absorb some of the earlier sections)? [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 07:15, 28 February 2013 (UTC)

== Bigmath ==

I'm surprised to see {{Tl|Bigmath}} used in the display formulae. I have not even seen it mentioned in previous arguments over LaTeX vs HTML; those arguments were over what to use for inline equations, while everyone seemed to prefer LaTeX for display. And no wonder - it is so much easier to use and looks so much better, especially when there are integral signs. [[User:RockMagnetist|RockMagnetist]] ([[User talk:RockMagnetist|talk]]) 05:29, 28 February 2013 (UTC)

:Yes, I used that to keep Incnis Mrsi happy (who seems to have strong opinions on the {{tl|math}}, {{tl|mvar}}, {{tl|bigmath}} templates), but it's very confusing since above he states above "to use math for expressions using a vinculum"... which includes ''all'' fractions, roots, derivatives... . I wrote in 1.2.1 to use {{tl|math}} ''inline'' and {{tl|bigmath}} ''or'' <nowiki><math></nowiki> for displayed. Due to the much more popular use of LaTeX for displayed formulae anyway, I agree that's what should be used, not bigmath. <small>Personal preferences of individual editors are not important for what is easier and is already a standard.</small>

:Exactly the same comment was stated at [[Wikipedia talk:WikiProject Physics#WP:PHYS does not have its Manual of Style yet|wikiproject physics]].
:In this case, I think we should keep that section at least for now (even if redundant); it can also include pointers to possible LaTeX/mathjax errors. We can always disperse it into other sections or delete it in the final stage. [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 07:15, 28 February 2013 (UTC)

== Does the code need to be displayed? ==

I find it ironic that there are several tables in which a usage that is not recommended is highlighted in red, along with the code to reproduce it. I don't see the point in providing the code for unwanted results. Indeed, I'm not sure the tables help. Most style guides display examples of the recommended style, and it is up to the reader to look at the source and see how they were produced. That is harder to do when the formulae are in tables. If you wish to make it easier to view the code, an alternative is to use footnotes. I will take the liberty of editing one of the tables to provide an example for comparison. [[User:RockMagnetist|RockMagnetist]] ([[User talk:RockMagnetist|talk]]) 18:50, 28 February 2013 (UTC)

:Those ideas/changes are mainly my fault, not Incnis Mrsi's...
:*I [http://en.wikipedia.org/enwiki/w/index.php?title=Wikipedia%3AMOSPHYS&diff=537573412&oldid=537566048 put the code for the "not-recommended" notation] to compare with the recommended, so editors know what code produces the unwanted results. 
:*Similarly [http://en.wikipedia.org/enwiki/w/index.php?title=Wikipedia%3AMOSPHYS&diff=541293988&oldid=541282093 recently removed footnotes] since they contained information that could just be stated there and then without having to scroll down to the very bottom of the page. 
:*<s>The code is there to make it ''easier to see how it is produced''... It seems a bit reversed that to say it's easier to make the reader read up the code when it's already directly next to the formula on site? I don't understand your point...</s>
:*Soon, I'm soon going to transform all displayed formulae to LaTeX, so don't give yourself that labour. [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 19:04, 28 February 2013 (UTC)

:Right - you just meant to click on "edit" and look at the ''source code''... (Stupid me!)... Fair point - feel free to delete those columns then. [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 19:14, 28 February 2013 (UTC)

::[http://en.wikipedia.org/enwiki/w/index.php?title=Wikipedia%3AMOSPHYS&diff=541319396&oldid=541298791 Code columns deleted]. [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 19:30, 28 February 2013 (UTC)

:::I'm not sure that footnotes are a great idea (they're certainly extra work), but I have provided an example. The easiest use is to just mouse over them and the code should be displayed (I don't know if that works for everyone). [[User:RockMagnetist|RockMagnetist]] ([[User talk:RockMagnetist|talk]]) 19:38, 28 February 2013 (UTC)

::::Ok, but why have you used {{tl|bigmath}} for the inner products when we just agreed not to use bigmath for display? And why remove the table? It was clearly presented that way, bullet points are no more compact since the text now fills the screen. [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 19:57, 28 February 2013 (UTC)

:::::The two of us agree that LaTeX should be used, but I decided to stick with the prevailing style until there was broader consensus. As for the table, I replaced it by two equations with footnotes; the rest of the text was already there. That way each example is right beside the discussion of it. I think you're way more fond of tables than most people; they should be used sparingly or the page starts to look cluttered. At any rate, my table-free example provides an alternative for other people to consider. [[User:RockMagnetist|RockMagnetist]] ([[User talk:RockMagnetist|talk]]) 20:05, 28 February 2013 (UTC)

Sorry - I didn't notice this reponse while just editing... Too many tables make the page look cluttered? (If anything the opposite IMO). Again IMO, the new style of "piping" the code into footnotes doesn't look very presentable (is this really going to apply to most/all expression on the page? lists of code in footnotes?), although can live with it for now. [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 20:28, 28 February 2013 (UTC)

:My experience has been that, after looking at a recommendation in one of the tables, I have to hunt around for the explanation. It's so much simpler to just provide the examples with the explanation. Which may be why tables are rare to nonexistent on other MOS pages (including [[MOS:MATH]]).

: As for the code, my real preference is to not display it at all and let people look at the page in their editor. I just presented this alternative in case there was some concern that many people wouldn't think to use the editor. [[User:RockMagnetist|RockMagnetist]] ([[User talk:RockMagnetist|talk]]) 20:39, 28 February 2013 (UTC)

::Don't get the wrong idea - it's good that you allow others to fill in on alternative presentations. Yes, [[MOS:MATH]] doesn't even have tables, and is a good example of a MoS in general I've been trying to follow (although trying to include tables). [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 20:44, 28 February 2013 (UTC)

:::I suppose one reason for having footnotes (or tables) is that we generally implement only one of HTML or LaTeX in our examples. I'm tempted to say that is o.k., though - by only providing the implementation we prefer, we can exert subtle pressure on editors to use it! [[User:RockMagnetist|RockMagnetist]] ([[User talk:RockMagnetist|talk]]) 20:45, 28 February 2013 (UTC)

== Some comments ==

You guys have done a lot of work since I last looked at this, really impressive! I thought I could just read it all through and give some comments, but it's too much and changing too fast... So here's just a few remarks on the first part, and I'll do some minor tweaks myself.
# ''Notation and typesetting in formulae:'' I still don't see the purpose of the first table: are the examples meant to define the subsections, or to show the typesetting? In both cases I would include them in their subsection, maybe trimmed down a bit to stay as concise as possible.
# ''Application of <nowiki><math>...</math> and {{math|...}}</nowiki>:'' I would remove the box around the rule of thumb. There's a lot of tables already and if everything is trying to stand out, nothing will. I wonder if we should replace the table with links to e.g. [[Wikipedia:Manual_of_Style/Mathematics#Typesetting_of_mathematical_formulae]] and [[Wikipedia:«math»]]. I don't understand the sentence after the table.
# ''Vectors and vector spaces:'' There's a number of parser errors when I look at this subsection while logged out. I think deprecating arrows is a good idea. I don't like the red cell background with nearly invisible grey borders. For consistency with the main MOS we could use green and red text, like in {{tl|xt}} but without switching to serif style. We could also steal the tooltip without footnote mechanism from there.
So much for now, I hope it's useful. Sorry for the telegraphic style. &mdash;&thinsp;[[User:Hhhippo|<span style="color:darkblue; font-family:times;">'''H<small>HHIPPO</small>'''</span>]] 20:44, 28 February 2013 (UTC)

:I love the tooltip idea! It's what I really wanted to do instead of footnotes but didn't know how. [[User:RockMagnetist|RockMagnetist]] ([[User talk:RockMagnetist|talk]]) 20:47, 28 February 2013 (UTC)
::Hmm, the disadvantage of these tooltips is that one can't copy and paste from them. But then they work without activating gadgets, and we really don't want the footnotes to display, so this might be the best solution for now. &mdash;&thinsp;[[User:Hhhippo|<span style="color:darkblue; font-family:times;">'''H<small>HHIPPO</small>'''</span>]] 21:07, 28 February 2013 (UTC)

In order of your points:

#The first table is an overview (apologies this was not adequately answered before...). Something will be done soon...
#Done - the table (I wrote) was just a waste of space and time anyway, this should be covered in depth in other manuals of styles.
#The parser errors are due to the \underleftarrow or \underrightarrow LaTeX commands, placed there intentionally to see if they would actually work (this is a draft!). Yes red/green text would be nice (but no point changing to another font... just the font colour) - cf above the forthcoming depreciation of tables.. 
[[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 20:55, 28 February 2013 (UTC)

:For point 1 the examples were included into the sections. Better? [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 21:14, 28 February 2013 (UTC)

::Yes. [[User:RockMagnetist|RockMagnetist]] ([[User talk:RockMagnetist|talk]]) 21:20, 28 February 2013 (UTC)

:::Yes, thanks! One might do some fine-tuning once the sections are done, but as you said, this is very much a work in progress.
:::A related thought: we're going down quite deep in the sub-sub-section tree, and it's easy to lose track of where you are when reading. Should we get rid of the first section's header and promote all its contents by one level? &mdash;&thinsp;[[User:Hhhippo|<span style="color:darkblue; font-family:times;">'''H<small>HHIPPO</small>'''</span>]] 21:26, 28 February 2013 (UTC)

::::Yes, feel free to make any adjustments. 
::::After creating so much chaos I should stay out of the way now, and let you guys carry on the good work... Thanks! [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 21:32, 28 February 2013 (UTC)

:::::I moved the typesetting to its own section since it is common to all kinds of mathematical display. [[User:RockMagnetist|RockMagnetist]] ([[User talk:RockMagnetist|talk]]) 22:04, 28 February 2013 (UTC)

I drafted two templates for coloring examples, in user space for now: [[User:Hhhippo/sxt]] and [[User:Hhhippo/!sxt]]. The differences to {{tl|xt}} and {{tl|!xt}} are that they don't change the font family and that they try to generate a default tooltip if no title= parameter is given. This doesn't work if the example includes &lt;math> tags or templates though, so in many cases we will still need to set title=&lt;nowiki>...</nowiki>.
I implemented them in [[Wikipedia:MOSPHYS#Sets and spaces|Sets and spaces]] as an example. Regarding the contents there: I think blackboard bold is ok, since inserting the unicode letters is easy with the CharInsert gadget. I don't have a strong opinion on how to typeset Lie groups or Hilbert spaces, other than that some recommendation would be nice to have. &mdash;&thinsp;[[User:Hhhippo|<span style="color:darkblue; font-family:times;">'''H<small>HHIPPO</small>'''</span>]] 20:28, 2 March 2013 (UTC) 

:I'm happy you're doing this. Not sure what the ''CharInsert gadget'' is though, will look into this. Thanks, [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 21:33, 2 March 2013 (UTC)
::Check the Gadgets tab in your user preferences, the last item under Editing. Maybe we should mention this somewhere. &mdash;&thinsp;[[User:Hhhippo|<span style="color:darkblue; font-family:times;">'''H<small>HHIPPO</small>'''</span>]] 21:41, 2 March 2013 (UTC)

:::It already was turned on, but I have never even used the toolbar underneath the edit browser, and that's where the symbols can be quickly inserted (in this case the "math and logic" option gives the blackboard bold letters (and more)). Thanks! Yes, perhaps it could be mentioned to slow editors (like me!) who may not realize this feature... [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 21:49, 2 March 2013 (UTC)

== Sources for guidelines? ==

Ideally, these guidelines should be more than just the personal tastes of a handful of editors. Should we try to follow a particular style guide - for example, the APA guide? I have added a Further reading section with a couple of sources. [[User:RockMagnetist|RockMagnetist]] ([[User talk:RockMagnetist|talk]]) 21:32, 28 February 2013 (UTC)

:True. [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 21:35, 28 February 2013 (UTC)

::It's good to have refs indeed, I'm not sure we can follow one completely though, we'll need to establish our own consensus, especially once we attempt to make this official. Personally I'm biased by once having worked as copy-editor for some [[Springer Science+Business Media|Springer]] journals, I think that's not too far away from AIP though. &mdash;&thinsp;[[User:Hhhippo|<span style="color:darkblue; font-family:times;">'''H<small>HHIPPO</small>'''</span>]] 21:46, 28 February 2013 (UTC)

== [[WP:MOSPHYS #Number sets]] ==

I am unhappy how this section starts. First, it is self-contradicting: code points placed at the [[Blackboard bold]] link belong to [[Mathematical Alphanumeric Symbols]] <tt>0x1D5??</tt> of [[Supplementary Multilingual Plane|SMP]], but symbols from the actual table, ℕ ℚ ℤ ℝ ℂ, are [[Letterlike Symbols]] <tt>0x21??</tt> of BMP (except for 𝔽 = '''F'''). Second, SMP characters are not especially common in default browser fonts, so their presence in the MoS project causes an astonishment. Unlike ℕ etc., they are absent even from MathJax_Main. [[User:Incnis Mrsi|Incnis Mrsi]] ([[User talk:Incnis Mrsi|talk]]) 21:41, 28 February 2013 (UTC)
:Isn't that just what [[Blackboard bold]] says, in the last paragraph of the lede? And I'm not sure we need the F here. &mdash;&thinsp;[[User:Hhhippo|<span style="color:darkblue; font-family:times;">'''H<small>HHIPPO</small>'''</span>]] 22:05, 28 February 2013 (UTC)

::I did say blackboard bold/double-struck/you-name-it in wikicode would be a nuisance above - so changed to <nowiki><math></nowiki>. Also '''F''' may be deleted, it's not really needed. [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 22:20, 28 February 2013 (UTC)
: [{{fullurl:WP:MOSPHYS|curid=38408659&diff=541357024}}] did not remove SMP characters, but introduced a new problem: the current wording implicitly recommends ''only'' &lt;math> for ℕ ℚ ℤ ℝ ℂ. Oh the other hand, we recommend to avoid &lt;math> in body text. Where is the truth? [[User:Incnis Mrsi|Incnis Mrsi]] ([[User talk:Incnis Mrsi|talk]]) 22:36, 28 February 2013 (UTC)

::Let's just settle what blackboard bold letters to use with {{tl|math}} inline instead of &lt;math> inline. If the [[Wikipedia:MOSPHYS#Sets and spaces|current ones]] are wrong, please insert the exact characters to use in that section. Thanks, [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 12:28, 1 March 2013 (UTC)

== Sidebar and navbox templates ==

Why do we have this section on a general Wikipedia style issue? If it agrees with [[Wikipedia:Categories, lists, and navigation templates]], it's redundant. And if it doesn't, why are we trying to make our own policy on such a matter? [[User:RockMagnetist|RockMagnetist]] ([[User talk:RockMagnetist|talk]]) 15:47, 1 March 2013 (UTC)

:The answer is at the end of [[Wikipedia talk:WikiProject Physics#Picture proposal for template:classical mechanics|this section]]. Are you going to delete it? I don't mind. [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 22:07, 1 March 2013 (UTC)

::I'll wait for other opinions, but my opinion is that there is nothing in that discussion or this section that applies only to physics articles. [[User:RockMagnetist|RockMagnetist]] ([[User talk:RockMagnetist|talk]]) 22:43, 1 March 2013 (UTC)

:::At the moment there's indeed nothing specific to physics here. The section came about when a discussion on sidebars vs. footers emerged on several physics pages, but stalled shortly after. It would probably be a good idea to define our own style within the rather broad existing policies and guidelines, but that needs some discussion. So if we don't have anything better than now by the time we're done with the rest, we should drop it for the time being. &mdash;&thinsp;[[User:Hhhippo|<span style="color:darkblue; font-family:times;">'''H<small>HHIPPO</small>'''</span>]] 21:56, 5 March 2013 (UTC)

== New section: [[WP:MOSPHYS#Conventions in WP articles and sources|Conventions in WP articles and sources]] ==

I [http://en.wikipedia.org/enwiki/w/index.php?title=Wikipedia%3AMOSPHYS&diff=541704811&oldid=541600133 added a new section] which may seem very trivial and obvious to everyone, but isn’t actually, and hasn't been mentioned yet in the page. Feedback as always helps. [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 11:53, 2 March 2013 (UTC)

== "Universal" sources? ==

Do others think a section listing the standard works very frequently cited is a good idea? Examples including:
*[[Paul Dirac|Dirac]]'s ''[[Principles of Quantum Mechanics]]'', 
*[[Charles Misner|Misner]], [[Kip Thorne|Thorne]] and [[John Archibald Wheeler|Wheeler]]'s ''[[Gravitation (book)|Gravitation]]'', 
*[[John David Jackson (physicist)|Jackson]]'s ''Classical Electrodyanamics'', 
*[[Herbert Goldstein|Goldstein]]'s ''[[Classical Mechanics (book)|Classical Mechanics]]''
*[[Wolfgang Pauli|Pauli]]'s books
*[[David Griffiths (physicist)|Griffiths']] books, 
*[[Lev Landau|Landau]] and [[Evgeny Lifshitz|Lifshitz]]'s ''[[Course of Theoretical Physics]]'', 
*''[[The Feynman Lectures on Physics]]'',
etc...

It sets an example of good sources. Thanks, [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 12:06, 2 March 2013 (UTC)

:Actually, probably not, on second thought. But I can't see any pages within WikiProject physics that list such references and IMO it should, because it increases awareness of reliable sources within the project. I'll get that later. [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 13:17, 2 March 2013 (UTC)

== Subscripts and superscripts ==

A few thoughts on that section:
# I would more generally say that sub/superscripts representing ''variables'', not just ''indices'' should be italic. For example, if you have an external magnetic field and want to discuss its time dependence at a fixed point ''x''<sub>0</sub>, you might write (in displaystyle) <math>\mathbf{B}_{x_0}^\mathrm{ext}(t)</math>, where ''x''<sub>0</sub> is not an index.
# What are the ''various typographical rules'' here? I see only one rule.
# I think this is the most important point about sub/superscripts and should come before the index notation part.
# Vector fields in 3D are often described as vectors rather than in index notation, and I don't think there's anything wrong with that.
# ''Ratios of differential (infinitesimal) quantities and derivatives'' has not much to do with sub/superscripts.
I'll give it a go later, just didn't want to interfere while you (Maschen) are working on the section. &mdash;&thinsp;[[User:Hhhippo|<span style="color:darkblue; font-family:times;">'''H<small>HHIPPO</small>'''</span>]] 11:30, 3 March 2013 (UTC)

:Your ideas are correct, although about 3d vector fields in index notation, are you referring to the end of the section [[WP:MOSPHYS‎#Vectors and vector spaces|Vectors and vector spaces]]? Of course vector calc in 3d doesn't need index notation, these are conventions Incnis Mrsi set (see the above first few sections on this page). The sections are growing almost anywhere but it's easy to move them around. I'll try and fix things now and not interfere later. Thanks, [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 12:10, 3 March 2013 (UTC)

::Once more, I hope you don't mind me copying your example (of the magnetic field this time). [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 12:17, 3 March 2013 (UTC)
:::No, feel free to use it if you like it. My point 4 was referring to [[WP:MOSPHYS#Index notation for tensors and spinors|Index notation for tensors and spinors]], which starts out with vector fields.
:::On second thought, I wonder if we should collect most of the 'italic/roman for variables/names' issue in the very beginning, as a fundamental rule (unless otherwise noted). At the moment this topic is scattered over various places with quite some overlap. I'll think about it a bit more before trying, but I have the feeling that can be done more efficiently. &mdash;&thinsp;[[User:Hhhippo|<span style="color:darkblue; font-family:times;">'''H<small>HHIPPO</small>'''</span>]] 12:33, 3 March 2013 (UTC)

::::Just finished the previous edit. That initial segment wasn't written by me, so I'll change that, and after try to factorize the roman/italic variables at the beginning in the new section [[WP:MOSPHYS#Greek typography|Greek typography]], which may have a title anme change. Thanks, [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 12:38, 3 March 2013 (UTC)
::::In the end I'm not sure how exactly to factorize all things italic/upright. Seems easier to just say it within the context... Maybe you mean to provide a short list of what is (and not) to be upright or italic? Feel free to edit from now on, I've ran out of editing time for today. [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 13:01, 3 March 2013 (UTC)
:::::I gave it a shot. There's more that can be compacted now by referring to the general roman vs. italic rule, but I have to leave now. Will continue tomorrow, but comments and tweaks are of course welcome. &mdash;&thinsp;[[User:Hhhippo|<span style="color:darkblue; font-family:times;">'''H<small>HHIPPO</small>'''</span>]] 17:23, 3 March 2013 (UTC)

::::::Nice start, so from there you can cut redundancy in the rest of the article. [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 17:45, 3 March 2013 (UTC)
: Why not to simply say that subscripts and superscripts shall be in the same style as corresponding writings usually appear? If the subscript refers to an (italicized) variable, then it should be italicized. If it refers to a substance or is just an abbreviation, then it should be Roman. [[User:Incnis Mrsi|Incnis Mrsi]] ([[User talk:Incnis Mrsi|talk]]) 17:59, 3 March 2013 (UTC)

::Yes; short, punchy, to the point. The examples (and counterexamples) could simply be taken out the sections and listed after, that should cut out considerable repetition. Will try it if no-one else does sometime tomorrow. [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 18:26, 3 March 2013 (UTC)
:::Agreed. We should describe the recommended style by formulating rules, not let people deduce the rules from a bunch of examples. In some cases an example might be good to ''illustrate'' a point, but we shouldn't rely on them to ''make'' a point. Many can probably go somewhere else or out entirely. &mdash;&thinsp;[[User:Hhhippo|<span style="color:darkblue; font-family:times;">'''H<small>HHIPPO</small>'''</span>]] 21:34, 3 March 2013 (UTC)

== Greek letters ==

Previous post by Maschen on this topic: {{tq|"What about typography of Greek letters? Their application for [[WP:MOSPHYS#Subscripts and superscripts|indices is included]], but what about when they're just used like any variable; say a [[wavefunction]] {{math|ψ, ''ψ''}}, or an angle {{math|θ, ''θ''}}? I think it's silly that lower case Greek isn't always italicized (look around WP physics and maths pages...)... Apart from tensor indices, ''why'' treat Greek and Latin alphabets different? We should just use {{math|''ψ''}} in exactly the same way as for {{math|''x''}}. This is ''partial'' though, since capital Greek looks ''slightly'' odd (IMO): {{math|''Φ, Ψ, Ω''}}... compare to {{math|''P'', ''J'', ''Y''}}..."}}
:I renamed and compacted the [[WP:MOSPHYS#Greek letters|Greek letters]] section quite a bit. I don't think we need lots of examples to show what looks better, the 'consistency with &lt;math>' argument is strong enough anyway. A remaining question that we should clarify is what to do if the letter does ''not'' appear in displayed math in the same article, and is used as a name rather than a variable, like in [[Rho meson]]. I would tend to always recommending lower case italic / upper case roman, for consistency with other articles. But there may be other opinions.
:I also compacted the part about variants and removed the application examples. I don't think they are needed here, unless we would want to define which variant is recommended for which application. &mdash;&thinsp;[[User:Hhhippo|<span style="color:darkblue; font-family:times;">'''H<small>HHIPPO</small>'''</span>]] 22:43, 4 March 2013 (UTC)

::No problem, keep editing, although the point of those Latin/Greek in HTML/LaTeX examples was to simply illustrate and the room occupied was inevitable. [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 23:29, 4 March 2013 (UTC)
:::Yes, it's not so easy to find the right middle ground, concise but still with enough explanation and illustration. We might need a few iterations. We could also start making more use of footnotes, they don't interrupt the flow of the 'story', but can provide background information or additional examples. &mdash;&thinsp;[[User:Hhhippo|<span style="color:darkblue; font-family:times;">'''H<small>HHIPPO</small>'''</span>]]

Italic/upright for particles seems to vary in the literature, maybe just use upright since that matches the upright for nuclide symbols and chemical/nuclear reactions? Here are a few links from Google: [http://xml.web.cern.ch/XML/pennames/heppennames2.pdf CERN], [http://desktop-publishing.web.cern.ch/desktop-publishing/Symbols_Units.pdf CERN], [http://xml.web.cern.ch/XML/pennames/pennameswww/node1.html CERN] (in the process found [http://physics.nist.gov/Pubs/SP811/sec10.html NIST],[http://www.gruppodelcolore.it/Docs/ISO_NIST_typefaces.pdf NIST], which are not as relevant for particles but perhaps the MoS itself). [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 22:11, 5 March 2013 (UTC)
:I'm undecided. Have put it in for now and marked as 'consensus needed'. Feel free to change it. &mdash;&thinsp;[[User:Hhhippo|<span style="color:darkblue; font-family:times;">'''H<small>HHIPPO</small>'''</span>]] 22:06, 6 March 2013 (UTC)

== [[:Template:vec]] ==

Although we already decided arrows may be depreciated, I nevertheless created {{tl|vec}} for left/right/doubleheaded arrows under/over a character, for use with {{tl|math}} with inline HTML, as some editors prefer to use <code>\vec</code> in LaTeX (not the full over/under arrow) for vectors which also applies to ''one'' character: <math>\vec{A}</math>. 

I'm sure we agree an allowance can be made for <code>\vec</code> as well as '''bold'''? Not all articles have to have an identical style, '''bold''' and <code>vec</code> are both used. 

It has been [http://en.wikipedia.org/enwiki/w/index.php?title=Wikipedia%3AMOSPHYS&diff=542408802&oldid=542116786 included] in the article. [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 22:01, 6 March 2013 (UTC)

== [[:Template:intmath]] ==

I created one more template, {{tl|intmath}}, for unicode [[integral symbol]]s in {{tl|math}}. The syntax is like LaTeX (see documentation). [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 21:49, 7 March 2013 (UTC)

===More markup messages===
Maschen, I'm seeing markup messages in Firefox  & Puffin browsers:

   " For Euclidean vectors, there are numerous conventions. The better notations for vectors use:
        bold: easy to typeset and print, and stands out, easily compatible with other diacritics), or
        \overrightarrow{\text{overarrows}} or Failed to parse (unknown function\underrightarrow): \underrightarrow{\text{underarrows}} "



  In bold italic section "

        A, \mathbf{A}, not A, \boldsymbol{A}
        Failed to parse (unknown function\underrightarrow): \overrightarrow{A}, \underrightarrow{A}, \underrightarrow{AB}, \overrightarrow{AB}, \underrightarrow{AB}"

+ blank space at 1st column of next line

    or "normal" or unit vectors, they can be bold, or a hat replaces the arrows:

        ê, \mathbf{\hat{e}}, \hat{e} , not Failed to parse (unknown function\underrightarrow): \overrightarrow{\hat{e}}, \underrightarrow{\hat{e}}

+ blank space at 1st column of next line


    There is also a specialized template {{braket}} for creating bra and ket vectors.

        |ψ⟩, |ψ⟩, ⟨ψ|, ⟨ψ|, \left|\psi\right\rangle, \left\langle\psi\right| , not Failed to parse (unknown function\underrightarrow): \overrightarrow{\psi}, \underrightarrow{\psi},\boldsymbol{\psi},\hat{\psi}

+ blank space at 1st column of next line

Under Other "
    Hilbert spaces: H, Failed to parse (unknown function\mathscr): \mathcal{H}, \mathscr{H}


+ blank space at 1st column before "or ℋ"
"
Thanks, --[[User:Ancheta Wis|Ancheta Wis]] [[User talk:Ancheta Wis| &nbsp; (talk]] [[Special:Contributions/Ancheta Wis| &#124; contribs)]] 17:40, 12 March 2013 (UTC)

:You are right to point out <code>\mathscr{}</code>, <code>\overleftarrow{}</code>, <code>\underleftarrow{}</code>, <code>\overrightarrow{}</code>, <code>\underrightarrow{}</code> - those only work in mathjax for some reason. Are you using mathjax or png in the Firefox & Puffin browsers? Those will definitely not render - they are tested here to see what does and doesn't work for editors as well as decide on conventions. Thanks, [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 17:54, 12 March 2013 (UTC)

== Small/wide/no hats for operators and vectors ==

In some contexts, particularly [[relativistic quantum mechanics]], operators and often unit vectors are required. The combinations of operator and vector notations which seem standard include:

#operators: no hats <math>\mathbf{p}</math>, unit vectors: small hats <math>\hat{\mathbf{e}}_i</math>
#operators: small hats <math>\hat{\mathbf{p}}</math>, unit vectors: no hats <math>\mathbf{e}_i</math>
#operators: no hats <math>\mathbf{p}</math>, unit vectors: no hats <math>\mathbf{e}_i</math>
#operators: wide hats <math>\widehat{\mathbf{p}}</math>, unit vectors: no hats <math>\mathbf{e}_i</math>
#operators: wide hats <math>\widehat{\mathbf{p}}</math>, unit vectors: small hats <math>\hat{\mathbf{e}}_i</math>

We should clarify this in the MOS.

My preference is 5, since 
*it's immediately clear that a hat is for an operator, and not too different to a small hat as used in other contexts, 
*small hats are frequently used for unit vectors to indicate that it's normalized (of course, without the small hats the context should state what is a unit vector and not, but the hats make it clear), and I've never seen unit vectors with wide hats, though they may be used by some authors.

I'm not saying to change all QM articles using small hats for operators to wide hats where there is consistency, but where the conflict arises (in relativistic QM articles) this would be my convention.

Any other potential problems with this? Are wide hats used for something else within the same context? Thanks, [[user:Maschen|'''M&and;''Ŝ''''']][[special:contributions/Maschen|''c''<sup>2</sup>''ħ''ε]][[user talk:maschen|''И<sub>τlk</sub>'']] 09:43, 22 June 2013 (UTC)