# The boundary condition

**URL:** <https://community.freefem.org/t/the-boundary-condition/3079>\
**Category:** General Discussion\
**Created:** [April 2, 2024, 12:04pm UTC](https://community.freefem.org/t/the-boundary-condition/3079 "2024-04-02T12:04:13Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![LXX](https://avatars.discourse-cdn.com/v4/letter/l/258eb7/32.png) [@LXX](https://community.freefem.org/u/LXX)\
**Post date:** [April 2, 2024, 12:04pm UTC](https://community.freefem.org/t/the-boundary-condition/3079/1 "2024-04-02T12:04:13Z")

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How to write the following three dimensions boundary condition in FreeFEM++?

 ![image](https://canada1.discourse-cdn.com/flex030/uploads/freefem/original/2X/5/54dcb0a896841f0938fba69b94c0d6df8b219cb6.png)

whre J=[0,T] is the time.

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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:** [April 2, 2024, 3:50pm UTC](https://community.freefem.org/t/the-boundary-condition/3079/2 "2024-04-02T15:50:11Z")

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This depend strongly of your formulation ans the finite element

Other wise you can make penalization.

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**Author:** ![LXX](https://avatars.discourse-cdn.com/v4/letter/l/258eb7/32.png) [@LXX](https://community.freefem.org/u/LXX)\
**Post date:** [April 3, 2024, 1:48am UTC](https://community.freefem.org/t/the-boundary-condition/3079/3 "2024-04-03T01:48:40Z")

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I do not quite understand. Are there any examples available for me to learn from?

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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:** [April 4, 2024, 4:39am UTC](https://community.freefem.org/t/the-boundary-condition/3079/4 "2024-04-04T04:39:57Z")

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The problem dépend of your variational formulation , of your equation and of your finite element

See maxwell exemple

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<div class="post-metadata">

**Author:** ![LXX](https://avatars.discourse-cdn.com/v4/letter/l/258eb7/32.png) [@LXX](https://community.freefem.org/u/LXX)\
**Post date:** [April 19, 2024, 7:39am UTC](https://community.freefem.org/t/the-boundary-condition/3079/5 "2024-04-19T07:39:10Z")

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Where can I find the Maxwell example?