[Rule] EXACT COVER BY 3-SETS to SET PACKING

[isPANN]

Source: EXACT COVER BY 3-SETS
Target: SET PACKING
Reference: Garey & Johnson, SP3, p.221

Specialization Note

This rule's source problem (EXACT COVER BY 3-SETS / X3C) is a specialization of MINIMUM SET COVERING (each set has exactly 3 elements, exact cover required). Implementation should wait until X3C is available as a codebase model.