Review Note

Let \(\rho\) be a relation from \(A\) to \(B\) and let \(\sigma\) be a relation from \(B\) to \(C\). Then the {{c1::composition of \(\rho\) and \(\sigma\)}}, denoted {{c2::\(\rho \circ \sigma \) (or also \(\rho \sigma\))}}, is the relation from {{c4::\(A\) to \(C\) }}defined by{{c2::{{c3::\[\rho \circ \sigma = \{(a, c) | \exists b ((a,b) \in \rho \wedge (b,c) \in \sigma)\}\]}}}}

dm22 skript d3.12