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Re^2: decomposing binary matricesby hv (Parson) 
on Feb 16, 2007 at 15:16 UTC ( #600455=note: print w/ replies, xml )  Need Help?? 
Thanks. First, I should note that there must be at least as many values as variables, since each variable must take a distinct value within the set of possible values. Second, variables that are part of an nelement submatrix need not have n bits set. The sparsest counterexample is: .. which can decompose into two 3element submatrices. The least sparse version of that is: .. which can decompose the same way. Update: swapped 2 bits in the last row of the sparse matrix, so it actually represents what I'm saying Hugo
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