:: deftheorem Def30 defines SourceMap CAT_6:def 30 :
for C being composable with_identities CategoryStr
for b₂ being Function of (Mor C),(Ob C) holds
( ( not C is empty implies ( b₂ = SourceMap C iff for f being Element of Mor C holds b₂ . f = dom f ) ) & ( C is empty implies ( b₂ = SourceMap C iff b₂ = {} ) ) );