for S being non empty non void ManySortedSign
for s being SortSymbol of S
for X being V5() ManySortedSet of the carrier of S
for x being Element of X . s
for t being Element of (Free (S,X))
for C being context of x
for s0 being SortSymbol of S
for x0 being Element of X . s0 st the_sort_of t = s & C is x0 -omitting & t is x0 -omitting holds
C -sub t is x0 -omitting