'Antihermitian predicate.
``Q.antihermitian(x)`` is true iff ``x`` belongs to the field of
antihermitian operators, i.e., operators in the form ``x*I``, where
``x`` is Hermitian.
References
.. [1] http://mathworld.wolfram.com/HermitianOperator.html'

@predicate_memo
def antihermitian(self):

    return Predicate('antihermitian')
