let V be set ; :: thesis: for C being finite set
for u being Element of
for X being set st X c= u holds
X is Element of
let C be finite set ; :: thesis: for u being Element of
for X being set st X c= u holds
X is Element of
let u be Element of ; :: thesis: for X being set st X c= u holds
X is Element of
let X be set ; :: thesis: ( X c= u implies X is Element of )
reconsider u' = u as Element of SubstitutionSet V,C by SUBSTLAT:def 4;
assume X c= u ; :: thesis: X is Element of
then X c= u' ;
then X in SubstitutionSet V,C by Lm4;
hence X is Element of by SUBSTLAT:def 4; :: thesis: verum