# Interpolation operator

**URL:** <https://community.freefem.org/t/interpolation-operator/1952>\
**Category:** General Discussion\
**Created:** [August 22, 2022, 8:14am UTC](https://community.freefem.org/t/interpolation-operator/1952 "2022-08-22T08:14:42Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![fotkara](https://avatars.discourse-cdn.com/v4/letter/f/a4c791/32.png) [@fotkara](https://community.freefem.org/u/fotkara)\
**Post date:** [August 22, 2022, 8:14am UTC](https://community.freefem.org/t/interpolation-operator/1952/1 "2022-08-22T08:14:42Z")

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Good morning,

I am new in FreeFem and I would like to get some information on the interpolation used between two meshes.

1. Given a problem with a Lagrange multiplier (e.g. the divergence free condition for the time-dependent Stokes problem), what will be the result of the interpolation between two meshes? The L2-divergence free projection? Something else?
2. Is that possible to try several types of interpolation or the user does not have any control on this?

Thank you so much in advance!  
Kind Regards,  
Fotini

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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:** [August 24, 2022, 8:11am UTC](https://community.freefem.org/t/interpolation-operator/1952/2 "2022-08-24T08:11:54Z")

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Yes write the formulation and try