for S1, S2 being non empty ManySortedSign
for f, g being Function
for C1 being non-empty MSAlgebra over S1
for C2 being non-empty MSAlgebra over S2 holds
( C1,C2 are_similar_wrt f,g iff ( S1,S2 are_equivalent_wrt f,g & the Sorts of C1 = the Sorts of C2 * f & the Charact of C1 = the Charact of C2 * g ) )