Derived restrictions in a combinatorial model

A computer program product comprising :

• a non-transitory computer readable medium retaining program instructions, which instructions when read by a processor, cause the processor to perform a method comprising:
• obtaining a combinatorial model defining a test space, the combinatorial model comprising a set of attributes, a respective domain for each attribute defining possible values for the attribute, and a set of restrictions, wherein the restrictions define a combination of values of the attributes that are restricted from the test space;
• and
• automatically determining a derived restriction that is derived from at least a first restriction and a second restriction, the first and second restrictions are comprised by the set of restrictions, wherein the derived restriction restricts at least one combination of values that is not restricted by the first restriction and at least one combination of values that is not restricted by the second restriction.