Corollary

A corollary (/ˈkɒrəlɛri/ KORR-əl-ur-ee or UK /kɒˈrɒləri/ ko-ROL-ər-ee) is a statement that follows readily from a previous statement.

In mathematics a corollary typically follows a theorem. The use of the term corollary, rather than proposition or theorem, is intrinsically subjective. Proposition B is a corollary of proposition A if B can readily be deduced from A or is self-evident from its proof, but the meaning of readily or self-evident varies depending upon the author and context. The importance of the corollary is often considered secondary to that of the initial theorem; B is unlikely to be termed a corollary if its mathematical consequences are as significant as those of A. Sometimes a corollary has a proof that explains the derivation; sometimes the derivation is considered self-evident.

Peirce on corollarial and theorematic reasonings