let V be set ; for C being finite set
for u being Element of (SubstLatt V,C)
for X being set st X c= u holds
X is Element of (SubstLatt V,C)
let C be finite set ; for u being Element of (SubstLatt V,C)
for X being set st X c= u holds
X is Element of (SubstLatt V,C)
let u be Element of (SubstLatt V,C); for X being set st X c= u holds
X is Element of (SubstLatt V,C)
let X be set ; ( X c= u implies X is Element of (SubstLatt V,C) )
reconsider u9 = u as Element of SubstitutionSet V,C by SUBSTLAT:def 4;
assume
X c= u
; X is Element of (SubstLatt V,C)
then
X c= u9
;
then
X in SubstitutionSet V,C
by Lm4;
hence
X is Element of (SubstLatt V,C)
by SUBSTLAT:def 4; verum