This function returns a matrix whose columns represent a basis for
the kernel of M. Calling the function twice on the same input will
not necessarily produce the same output, though in each case, a basis
for the kernel is produced.
This function works only on matrices whose entries are in a field
(from version CoCoA-5.0.3). See LinKerZZ for computing a
ZZ-basis for the kernel of M.
The output as it was given by CoCoA-4 (the basis of the ker) is
now given by LinKerBasis. See also HilbertBasisKer.
To clarify: if K := LinKer(M); then M*K is a zero matrix.