Documentation

Mathematica Teacher's Edition

Built-in Functions

Lists and Matrices

Matrix Operations

NullSpace

NullSpace[m] gives a list of vectors that forms a basis for the null space of the matrix m.

NullSpace works on both numerical and symbolic matrices.
NullSpace[m, Modulus->n] finds null spaces for integer matrices modulo n.
See The Mathematica Book on the web: Section 3.7.8.
See also: LinearSolve, RowReduce.

Further Examples