:: deftheorem Def9 defines stable MSUALG_6:def 9 :
for S being non empty non void ManySortedSign
for A being MSAlgebra over S
for R being ManySortedRelation of A holds
( R is stable iff for h being Endomorphism of A
for s being SortSymbol of S
for a, b being set st [a,b] in R . s holds
[((h . s) . a),((h . s) . b)] in R . s );