Corollary

A corollary is a mathematical statement which follows easily from a previously proven statement, typically a mathematical theorem. The use of the name corollary in place of proposition or theorem is usually subjective: proposition A is a corollary of proposition B if A can be deduced quickly and easily from B, but the meaning of "quickly and easily" varies depending upon the author and context. Sometimes a corollary has a proof which explains the derivation; sometimes the derivation is considered to be self-evident.