It is not clear which values and combination of values are allowed for the elements in the dimensions array of matrices.

Suggestion for valid configurations:
[-1;-1;-1] for null matrix (according to array with length -1)
[0;0;0] for emtpy matrix (according to array with length 0)
[n>0;n>0;n>0] for all remaining configurations

Values < -1 should not be allowed.
0 or -1 in combination with values > 0 should not be allowed. (i.e. [-1;1;1])

Current stacks seem to preserve the input values which creates difficulties for the applications.

Stack should not try to "correct" invalid values but reject them.
The compliance test tool should provide tests with valid and invalid values.