Version: Mathematica 13.0

IsomorphicSubgraphQ is used to determine whether a graph has a subgraph isomorphic to another graph. It was introduced by Mathematica 13. But it seems that there is a bug in IsomorphicSubgraphQ.

G1 = Graph[
   "Graph6"], VertexLabels -> Automatic]; 

![enter image description here

The graph below is a subgraph of the graph above.

subG1 = 
 Graph[ImportString["SsCAJ?`K?O`?@@@??WG@B?M??K??EG??{", "Graph6"], 
  VertexLabels -> Automatic];

enter image description here

But here's the “surprise”:

IsomorphicSubgraphQ[subG1, G1]


IGSubisomorphicQ in IGraphM backpack gives the right answer: True.

<< IGraphM`
IGSubisomorphicQ[subG1, G1]


  • $\begingroup$ I have Mathematica 13.0 version too but it returned me True. Isn't it an error on your side? $\endgroup$ Aug 20, 2022 at 13:08
  • $\begingroup$ That's weird. Are you running on the Windows version? $\endgroup$
    – licheng
    Aug 20, 2022 at 13:17
  • $\begingroup$ Yes, Windows 10. Restart kernel and try again. $\endgroup$ Aug 20, 2022 at 13:19
  • $\begingroup$ @azerbajdzan Thanks. I tried your way and it didn't work. Maybe some of the files were corrupted. I don't know why, I updated it to 13.1, now it's OK $\endgroup$
    – licheng
    Aug 21, 2022 at 9:16

1 Answer 1


OK in version 13.1 on Windows 10:

G1 = Graph[ImportString["W|tNHEpCKoh`@@Po_WHB@CKC?WGO{G?KKCB`?OMG?_y_?Sn", 
"Graph6"], VertexLabels -> Automatic]
subG1 = Graph[ImportString["SsCAJ?`K?O`?@@@??WG@B?M??K??EG??{", "Graph6"], 
VertexLabels -> Automatic]
IsomorphicSubgraphQ[subG1, G1]


  • $\begingroup$ Thanks for telling, it seems to be fixed in the new version. I did not see any any record of it being fixed on the new 13.1 feature though. $\endgroup$
    – licheng
    Aug 20, 2022 at 12:40

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