null (Matlab function) Null space of a matrix

## Matlab/Scilab equivalent

Matlab | Scilab
    null(a)
    null(a, 'r')
    % No equivalent
    % No equivalent
    kernel(a)
    // No equivalent
    kernel(a, tolerance)
    kernel(a, tolerance, "qr")

## Examples

Matlab | Scilab
    a = [1 3 2; 2 -3 -5];
    null(a)
    size(null(a),2)
    a = [1 3 2; 2 -3 -5];
    kernel(a)
    size(kernel(a),2) // Nullity of a