  The role of associativity or WDVV equations in effective supersymmetric
quantum theories is discussed and it is demonstrated that for wide class of
their solutions when residue formulas are valid the proof of associativity
equations can be reduced to solving the system of ordinary linear equations and
depends only upon corresponding matching and nondegeneracy conditions. The
covariance of WDVV equations upon generic duality transformations and the role
of associativity equations in general context of quasiclassical integrable
systems is also discussed.
