let o, m be set ; for a, b being Object of (1Cat o,m)
for f being Morphism of (1Cat o,m) holds f is Morphism of a,b
let a, b be Object of (1Cat o,m); for f being Morphism of (1Cat o,m) holds f is Morphism of a,b
let f be Morphism of (1Cat o,m); f is Morphism of a,b
f in Hom a,b
by Th36;
hence
f is Morphism of a,b
by Def7; verum