for S being non empty non void ManySortedSign
for A being non-empty MSAlgebra over S
for C1, C2 being MSCongruence of A
for G being ManySortedFunction of (QuotMSAlg (A,C1)),(QuotMSAlg (A,C2)) st ( for i being Element of S
for x being Element of the Sorts of (QuotMSAlg (A,C1)) . i
for xx being Element of the Sorts of A . i st x = Class (C1,xx) holds
(G . i) . x = Class (C2,xx) ) holds
G is_epimorphism QuotMSAlg (A,C1), QuotMSAlg (A,C2)