# Mixed dimensional finite element

**URL:** <https://community.freefem.org/t/mixed-dimensional-finite-element/1588>\
**Category:** General Discussion\
**Created:** [March 7, 2022, 8:55pm UTC](https://community.freefem.org/t/mixed-dimensional-finite-element/1588 "2022-03-07T20:55:42Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![sebaubal](https://avatars.discourse-cdn.com/v4/letter/s/54ee81/32.png) [@sebaubal](https://community.freefem.org/u/sebaubal)\
**Post date:** [March 7, 2022, 8:55pm UTC](https://community.freefem.org/t/mixed-dimensional-finite-element/1588/1 "2022-03-07T20:55:42Z")

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Hello. I would like to formulate a problem that couples physics in a 2D domain and a different physics in part of the boundary of the 2d domain (thus, a 1d domain). Is there a mixed dimensional finite element type already implemented in FreeFEM that adapts to this need? It should be P2 in the 2d domain and piecewise quadratic continous in the 1d domain (part of the boundary of the 1d domain). Could you please point me to any relevant documentation and/or examples? Thank you  
Sebastian

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**Author:** ![frederichecht](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/frederichecht/32/15_2.png) [@frederichecht](https://community.freefem.org/u/frederichecht)\
**Post date:** [March 8, 2022, 5:25pm UTC](https://community.freefem.org/t/mixed-dimensional-finite-element/1588/2 "2022-03-08T17:25:04Z")

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I have do a small example 2 Laplace equation

[couple-2d-1d.edp](https://community.freefem.org/uploads/short-url/mblgGXNJAJ6ZkD54zPehPLTeNNV.edp) (1.1 KB)

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**Author:** ![sebaubal](https://avatars.discourse-cdn.com/v4/letter/s/54ee81/32.png) [@sebaubal](https://community.freefem.org/u/sebaubal)\
**Post date:** [March 9, 2022, 3:41pm UTC](https://community.freefem.org/t/mixed-dimensional-finite-element/1588/3 "2022-03-09T15:41:30Z")

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Thank you very much Frédéric! Kind regards,  
Sebastian