Orthogonal ray graphs and nano-PLA design

The logic mapping problem and the problem of finding a largest square sub-crossbar with no defects in a nano-crossbar with nonprogrammable crosspoint defects and disconnected wire defects have been known to be NP-hard. This paper shows that for nano-crossbars with only disconnected wire defects, the former remains NP-hard, while the latter can be solved in polynomial time.