for n being natural non empty number
for J being non empty non void Signature
for T being non-empty VarMSAlgebra over J
for X being V2() GeneratorSet of T
for S being non empty non void b₂ -extension b₁ PC-correct QC-correct b₁ AL-correct essential AlgLangSignature over Union X
for L being non empty IfWhileAlgebra of X,S
for A, V being Formula of L
for H being AL-theory of V,L
for a being SortSymbol of J
for x, y being Element of X . a
for x0, y0 being Element of Union (X extended_by ({}, the carrier of S)) st x = x0 & y = y0 holds
((x := ((@ y),L)) * A) \iff (A / (x0,y0)) in H