Minimal and Maximal Critical Sets in Room Squares

In this paper we introduce critical sets in Room squares. We give the cardinality of the minimal critical sets (min. cs) and maximal critical sets (max. cs) for inequivalence classes of Room squares of side 7,9, and 11. We also describe algorithms to compute min. cs and max. cs and conjecture the lower and upper bounds for min. cs and max. cs.