theorem Th15: :: MSATERM:15

for S being non empty non void ManySortedSign
for V being non-empty ManySortedSet of the carrier of S
for A being MSAlgebra over S
for t being c-Term of A,V
for s being SortSymbol of S
for x being set st x in the Sorts of A . s & t = root-tree [x,s] holds
the_sort_of t = s