:: deftheorem Def22 defines [| CAT_7:def 22 :
for C, C1, C2 being category
for F1 being Functor of C1,C st F1 is covariant holds
for F2 being Functor of C2,C st F2 is covariant holds
[|F1,F2|] = the pullback of F1,F2 `1_3 ;