let x be set ; for S being non void Signature
for Y being V5() ManySortedSet of
for X being ManySortedSet of the carrier of S
for s being SortSymbol of st x in (S -Terms X,Y) . s holds
x is Term of the carrier of (DTConMSA Y),
let S be non void Signature; for Y being V5() ManySortedSet of
for X being ManySortedSet of the carrier of S
for s being SortSymbol of st x in (S -Terms X,Y) . s holds
x is Term of the carrier of (DTConMSA Y),
let Y be V5() ManySortedSet of ; for X being ManySortedSet of the carrier of S
for s being SortSymbol of st x in (S -Terms X,Y) . s holds
x is Term of the carrier of (DTConMSA Y),
let X be ManySortedSet of the carrier of S; for s being SortSymbol of st x in (S -Terms X,Y) . s holds
x is Term of the carrier of (DTConMSA Y),
let s be SortSymbol of ; ( x in (S -Terms X,Y) . s implies x is Term of the carrier of (DTConMSA Y), )
assume
x in (S -Terms X,Y) . s
; x is Term of the carrier of (DTConMSA Y),
then
x in { t where t is Term of the carrier of (DTConMSA Y), : ( the_sort_of t = s & variables_in t c= X ) }
by Def6;
then
ex t being Term of the carrier of (DTConMSA Y), st
( x = t & the_sort_of t = s & variables_in t c= X )
;
hence
x is Term of the carrier of (DTConMSA Y),
; verum