# Mixed Function Spaces in Fenicsx

**URL:** <https://fenicsproject.discourse.group/t/mixed-function-spaces-in-fenicsx/16502>\
**Category:** General\
**Tags:** dolfinx\
**Created:** [December 12, 2024, 2:40am UTC](https://fenicsproject.discourse.group/t/mixed-function-spaces-in-fenicsx/16502 "2024-12-12T02:40:54Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![dokken](https://yyz2.discourse-cdn.com/free1/user_avatar/fenicsproject.discourse.group/dokken/32/1560_2.png) [@dokken](https://fenicsproject.discourse.group/u/dokken)\
**Post date:** [December 12, 2024, 5:52am UTC](https://fenicsproject.discourse.group/t/mixed-function-spaces-in-fenicsx/16502/2 "2024-12-12T05:52:36Z")

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As stated on the top of the link you sent:

> **Note: this is documentation for an old release. View the latest documentation at [docs.fenicsproject.org/dolfinx/v0.9.0/python/demos.html](https://docs.fenicsproject.org/dolfinx/v0.9.0/python/demos.html)**

If you go to the latest documentation, you’ll find  
[https://docs.fenicsproject.org/dolfinx/v0.9.0/python/search.html?q=MixedFunctionSpace&check\_keywords=yes&area=default](https://docs.fenicsproject.org/dolfinx/v0.9.0/python/search.html?q=MixedFunctionSpace&check_keywords=yes&area=default)  
along with

> **[FEniCS release notes](https://fenicsproject.org/blog/v0.9.0/#extract-blocks)**
>
> Open-source finite element library

Additional resources include  
[http://jsdokken.com/FEniCS-workshop/src/multiphysics/submeshes.html](http://jsdokken.com/FEniCS-workshop/src/multiphysics/submeshes.html)  
[http://jsdokken.com/FEniCS-workshop/src/multiphysics/coupling.html](http://jsdokken.com/FEniCS-workshop/src/multiphysics/coupling.html)  
and

> [@Discontinuity at interface using mixed domains](https://fenicsproject.discourse.group/t/discontinuity-at-interface-using-mixed-domains/15040):
>
> Hi all, Exactly like in [this topic](https://fenicsproject.discourse.group/t/imposing-a-discontinuity-at-interface-using-dg-method/11780/18) I am trying to impose a discontinuity at an interface between two subdomains. This time having two subdomains with only CG elements and coupling them with a dS term. @dokken published [this gist](https://gist.github.com/jorgensd/8a5c32f491195e838f5863ca88b27bce#file-problem-py) that I am trying to adapt in order to have: \frac{u(-)}{K(-)} = \frac{u(+)}{K(+)} \nabla u(-) - \nabla u(+) = 0 However I am struggling to adapt the interface terms to achieve the desired result. This is the DG formulation we had earlier: # Interface F += - dot…

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_[View the full topic](https://fenicsproject.discourse.group/t/mixed-function-spaces-in-fenicsx/16502)._