theorem Th157: :: MSAFREE5:99

for S being non empty non void ManySortedSign
for s being SortSymbol of S
for X being non-empty ManySortedSet of the carrier of S
for x1, x2 being Element of X . s
for T being b₃,b₁ -terms all_vars_including inheriting_operations free_in_itself MSAlgebra over S holds (Hom (T,x1,x2)) ** (Hom (T,x1,x2)) = id the Sorts of T