#### How Nonlinear Residues Are Made to Disappear

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