# subgraph\_isomorphisms for considering absent edge

**URL:** <https://igraph.discourse.group/t/subgraph-isomorphisms-for-considering-absent-edge/1697>\
**Category:** Usage\
**Tags:** R\
**Created:** [6 November 2023 19:59 UTC](https://igraph.discourse.group/t/subgraph-isomorphisms-for-considering-absent-edge/1697 "2023-11-06T19:59:59Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Huimin721](https://yyz2.discourse-cdn.com/free1/user_avatar/igraph.discourse.group/huimin721/32/1007_2.png) [@Huimin721](https://igraph.discourse.group/u/Huimin721)\
**Post date:** [6 November 2023 19:59 UTC](https://igraph.discourse.group/t/subgraph-isomorphisms-for-considering-absent-edge/1697/1 "2023-11-06T19:59:59Z")

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Hi everyone!

I’m running subgraph\_isomorphisms with V2 method and get a question here:  
if I query pattern:  
g1 = make\_graph(edges =c(1,2,2,3,1,3), directed = FALSE)  
with color1 = c(1,2,3)  
g2 = make\_graph(edges =c(1,2,2,3), directed = FALSE)  
with color2 = c(1,2,3)

in the same big graph, the result produced by g1 is actually a subset of the result of g2.  
Could I ask in this case, if I do not want patterns that connect 1 and 3, how do I query with the function?  
Thanks so much and please let me know if I could provide other informations!

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**Author:** ![szhorvat](https://yyz2.discourse-cdn.com/free1/user_avatar/igraph.discourse.group/szhorvat/32/3_2.png) [@szhorvat](https://igraph.discourse.group/u/szhorvat)\
**Post date:** [6 November 2023 20:02 UTC](https://igraph.discourse.group/t/subgraph-isomorphisms-for-considering-absent-edge/1697/2 "2023-11-06T20:02:37Z")

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Use the `'lad'` method and set `induced=TRUE`

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<div class="post-metadata">

**Author:** ![Huimin721](https://yyz2.discourse-cdn.com/free1/user_avatar/igraph.discourse.group/huimin721/32/1007_2.png) [@Huimin721](https://igraph.discourse.group/u/Huimin721)\
**Post date:** [6 November 2023 20:25 UTC](https://igraph.discourse.group/t/subgraph-isomorphisms-for-considering-absent-edge/1697/3 "2023-11-06T20:25:52Z")

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Thank you. Could I ask what if my nodes have colors? Does lad also support node color? I did not see color arguments for lad.

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<div class="post-metadata">

**Author:** ![szhorvat](https://yyz2.discourse-cdn.com/free1/user_avatar/igraph.discourse.group/szhorvat/32/3_2.png) [@szhorvat](https://igraph.discourse.group/u/szhorvat)\
**Post date:** [6 November 2023 20:38 UTC](https://igraph.discourse.group/t/subgraph-isomorphisms-for-considering-absent-edge/1697/4 "2023-11-06T20:38:57Z")

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Yes, you can achieve the same by using an appropriate `domains` argument. For each vertex, give the list of other vertices with the same colour. See the documentation for details. I’m sorry, I don’t have time to write an example now.