Skip to main content

You are not logged in. Your edit will be placed in a queue until it is peer reviewed.

We welcome edits that make the post easier to understand and more valuable for readers. Because community members review edits, please try to make the post substantially better than how you found it, for example, by fixing grammar or adding additional resources and hyperlinks.

24
  • \$\begingroup\$ Ah, property X is on columns, not rows. \$\endgroup\$
    – Optimizer
    Commented Nov 5, 2014 at 7:26
  • \$\begingroup\$ As written, the 1 by 2 matrix 01 has property X because the set of the first column has the same vector sum as the empty set. Perhaps you meant nonempty sets of columns? I think it's cleaner not to change it though. \$\endgroup\$
    – xnor
    Commented Nov 5, 2014 at 7:50
  • 2
    \$\begingroup\$ The easiest reading of the rules is still that 01 has property X: (1) = (0) + (1). If you want to exclude that then you should say that the two sets of columns must be disjoint. \$\endgroup\$ Commented Nov 5, 2014 at 9:19
  • 1
    \$\begingroup\$ This question will give much insight on this problem (on how hard it is to check property X, which is NP-hard, unfortunately) mathoverflow.net/questions/157634/… \$\endgroup\$
    – justhalf
    Commented Nov 6, 2014 at 8:51
  • 3
    \$\begingroup\$ Currently we are just brute-forcing all the 2^m column combinations to check property X. If we could somehow devise a "meet in the middle" scheme (see the "subset sum" problem) this could probably reduce that to m * 2^(m/2)... \$\endgroup\$
    – kennytm
    Commented Nov 7, 2014 at 20:11