Go backward to Inverse of a RelationGo up to TopGo forward to Visualization |

*Definition: composition of two binary relations R and S.*

RoS:= {<a,c>:ain domain(R) /\cin range(S) /\( existsb: <a,b> inR/\ <b,c> inS)}.

*Proposition:* The composition of a relation from `A` to `B`
and of a relation from `B` to `C` is a relation from `A` to
`C`.

forallR,S,A,B,C:( RsubsetAxB/\SsubsetBxC) =>RoSsubsetAxC.

Author: Wolfgang Schreiner

Last Modification: October 14, 1999