let o, m be set ; :: thesis: for a, b being Object of (1Cat o,m)
for f being Morphism of (1Cat o,m) holds f in Hom a,b
let a, b be Object of (1Cat o,m); :: thesis: for f being Morphism of (1Cat o,m) holds f in Hom a,b
let f be Morphism of (1Cat o,m); :: thesis: f in Hom a,b
dom f = o by TARSKI:def 1;
then ( dom f = a & cod f = b ) by TARSKI:def 1;
hence f in Hom a,b ; :: thesis: verum