'Singular matrix predicate.
A matrix is singular iff the value of its determinant is 0.
Examples
>>> from sympy import Q, ask, MatrixSymbol
>>> X = MatrixSymbol(\'X\', 4, 4)
>>> ask(Q.singular(X), Q.invertible(X))
False
>>> ask(Q.singular(X), ~Q.invertible(X))
True
References
.. [1] http://mathworld.wolfram.com/SingularMatrix.html'

@predicate_memo
def singular(self):

    return Predicate('singular')
