Binding variables that appear in nonlinear residues will reduce the complexity of the nonlinear expressions and eventually results in linear expressions:

clp(q) ?-{exp(X+Y+1,2) = 3*X*X+Y*Y}.clpq:{Y*2-X^2*2+Y*X*2+X*2+1=0}

Equating `X` and `Y` collapses the expression completely and
even determines the values of the two variables:

clp(q) ?-{exp(X+Y+1,2) = 3*X*X+Y*Y}, X=Y.X = -1/4, Y = -1/4

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