New partial projective plane

In 2011, Roy completed a search for projective planes of order ten.  His search for weight 15 codewords was based on completing the last 36 columns of the representation given by MacWilliams, Sloane, and Thompson.  These columns may be split into six blocks of six columns each, where each block consists of the columns incident to one of the first six rows.  The entries in the first block may be uniquely specified up to equivalence by using row permutations to order the rows in lexicographic order.  Roy finds exactly 79 inequivalent ways of completing the second block.  His search attempts to extend each of the 79 cases to the later blocks, but in each case finds no way to perform the extension to the fourth block.

In order to verify his search we derived a SAT instance attempting to complete columns 76–111 and all rows 1–111.  Surprisingly, the SAT instance generated in this way was found to be satisfiable.  We found a completion of all six blocks, and therefore there should exist some symmetry of this completion that transforms the first two blocks into one of the 79 representatives used in the previous search (regardless of how those representatives were chosen).  Thus, we are forced to conclude that the previous search was incomplete.

The following is an explicit representation of an 111 by 51 partial projective plane that we found, where columns 76–111 have been ordered to appear immediately following columns 1–15.


111110000000000111111000000000000000000000000000000
100001111000000000000111111000000000000000000000000
010001000111000000000000000111111000000000000000000
001000100100110000000000000000000111111000000000000
000100010010101000000000000000000000000111111000000
000010001001011000000000000000000000000000000111111
100000000100001000000000000000000000000000000000000
100000000010010000000000000000000000000000000000000
100000000001100000000000000000000000000000000000000
010000100000001000000000000000000000000000000000000
010000010000010000000000000000000000000000000000000
010000001000100000000000000000000000000000000000000
001001000000001000000000000000000000000000000000000
001000010001000000000000000000000000000000000000000
001000001010000000000000000000000000000000000000000
000101000000010000000000000000000000000000000000000
000100100001000000000000000000000000000000000000000
000100001100000000000000000000000000000000000000000
000011000000100000000000000000000000000000000000000
000010100010000000000000000000000000000000000000000
000010010100000000000000000000000000000000000000000
100000000000000000000000000100000100000100000100000
100000000000000000000000000010000010000010000010000
100000000000000000000000000001000001000001000001000
100000000000000000000000000000100000100000100000100
100000000000000000000000000000010000010000010000010
100000000000000000000000000000001000001000001000001
010000000000000000000100000000000000001000010010000
010000000000000000000010000000000000010000001100000
010000000000000000000001000000000000100010000000010
010000000000000000000000100000000001000100000000001
010000000000000000000000010000000010000000100001000
010000000000000000000000001000000100000001000000100
001000000000000000000100000100000000000010000000001
001000000000000000000010000010000000000100000000010
001000000000000000000001000001000000000000010000100
001000000000000000000000100000100000000000001001000
001000000000000000000000010000010000000001000010000
001000000000000000000000001000001000000000100100000
000100000000000000000100000010000001000000000100000
000100000000000000000010000100000000100000000010000
000100000000000000000001000000010100000000000001000
000100000000000000000000100000001010000000000000100
000100000000000000000000010001000000001000000000010
000100000000000000000000001000100000010000000000001
000010000000000000000100000001000100000000001000000
000010000000000000000010000000100010000000010000000
000010000000000000000001000100000001000000100000000
000010000000000000000000100010000000100001000000000
000010000000000000000000010000001000010010000000000
000010000000000000000000001000010000001100000000000
000001000000000100000000000000000100000000100000010
000001000000000010000000000000000010000001000000001
000001000000000001000000000000000001000000001010000
000001000000000000100000000000000000100000010100000
000001000000000000010000000000000000010100000000100
000001000000000000001000000000000000001010000001000
000000100000000100000000000010000000000000001000100
000000100000000010000000000100000000000000010001000
000000100000000001000000000000010000000000100000001
000000100000000000100000000000001000000001000000010
000000100000000000010000000001000000000010000100000
000000100000000000001000000000100000000100000010000
000000010000000100000000000001000000100000000000001
000000010000000010000000000000100001000000000000010
000000010000000001000000000100000000001000000000100
000000010000000000100000000010000000010000000001000
000000010000000000010000000000001100000000000010000
000000010000000000001000000000010010000000000100000
000000001000000100000000000000001001000000010000000
000000001000000010000000000000010000100000001000000
000000001000000001000000000000100100000010000000000
000000001000000000100000000001000010000100000000000
000000001000000000010000000010000000001000100000000
000000001000000000001000000100000000010001000000000
000000000100000100000100000000000000000100000001000
000000000100000010000010000000000000000010000000100
000000000100000001000001000000000000000001000100000
000000000100000000100000100000000000000000100010000
000000000100000000010000010000000000000000010000001
000000000100000000001000001000000000000000001000010
000000000010000100000001000000000000010000000010000
000000000010000010000000100000000000001000000100000
000000000010000001000100000000000010000000000000010
000000000010000000100010000000000100000000000000001
000000000010000000010000001000000000100000000001000
000000000010000000001000010000000001000000000000100
000000000001000100000010000000000000001001000000000
000000000001000010000100000000000000010000100000000
000000000001000001000000010000000000100100000000000
000000000001000000100000001000000001000010000000000
000000000001000000010001000000000010000000001000000
000000000001000000001000100000000100000000010000000
000000000000100100000000010000100000000000000100000
000000000000100010000000001001000000000000000010000
000000000000100001000010000000001000000000000001000
000000000000100000100100000000010000000000000000100
000000000000100000010000100100000000000000000000010
000000000000100000001001000010000000000000000000001
000000000000010100000000100000010000000010000000000
000000000000010010000001000000001000000100000000000
000000000000010001000000001010000000000000010000000
000000000000010000100000010100000000000000001000000
000000000000010000010100000000100000000001000000000
000000000000010000001010000001000000000000100000000
000000000000001100000000001100000010000000000000000
000000000000001010000000010010000100000000000000000
000000000000001001000000100001000000010000000000000
000000000000001000100001000000100000001000000000000
000000000000001000010010000000010001000000000000000
000000000000001000001100000000001000100000000000000