# Mixed function space with dolfinx - how to implement an integral constraint

**URL:** <https://fenicsproject.discourse.group/t/mixed-function-space-with-dolfinx-how-to-implement-an-integral-constraint/9672>\
**Category:** dolfinx\
**Created:** [November 3, 2022, 5:50pm UTC](https://fenicsproject.discourse.group/t/mixed-function-space-with-dolfinx-how-to-implement-an-integral-constraint/9672 "2022-11-03T17:50:54Z")\
**Posts on this page:** 1\
**Showing post:** 5

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**Author:** ![francesco-ballarin](https://avatars.discourse-cdn.com/v4/letter/f/f05b48/32.png) [@francesco-ballarin](https://fenicsproject.discourse.group/u/francesco-ballarin)\
**Post date:** [December 6, 2023, 5:34am UTC](https://fenicsproject.discourse.group/t/mixed-function-space-with-dolfinx-how-to-implement-an-integral-constraint/9672/5 "2023-12-06T05:34:05Z")

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See recent posts on this topic:

- [How can I use Block Forms, Multiphenicsx, and Lagrange Multipliers to Solve Poisson's Equation with Pure Neumann Boundary Conditions? - #4 by francesco-ballarin](https://fenicsproject.discourse.group/t/how-can-i-use-block-forms-multiphenicsx-and-lagrange-multipliers-to-solve-poissons-equation-with-pure-neumann-boundary-conditions/12911/4) (go to the tutorial listed in the accepted solution, and notice that the case without domain decomposition does not actually require `multiphenicsx`)
- [Singular poisson equation in DOLFINx](https://fenicsproject.discourse.group/t/singular-poisson-equation-in-dolfinx/12632) (click on the link in the second post)

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