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Sporadic neighbour-transitive codes in Johnson graphs

From this page one can download a GAP program together with data to investigate 22 error correcting codes coming from Johnson graphs. The codes and the computations to deal with them are described in detail in the paper "Sporadic neighbour-transitive codes in Johnson graphs" by Cheryl Praeger and me, see my list of publications for details.

Here are two GAP files: neighbourgroup.h contains the code and neighbourtransitivecodes.g contains the data.


  1. Download the above two GAP readable files.
  2. Start GAP (version >= 4.5), you also need the orb package installed.
  3. From the command line, type Read("neighbourtransitivecodes.g"); in GAP.
  4. After that, a global variable named ntcodes is bound containing all the data for 22 codes.
  5. You can now do
    c := InvestigateNeighbourTransitiveCode(ntcodes[i].g,ntcodes[i].h);
    where i is to be replaced by some number between 1 and 22. The resulting record c describes the code.