# Change of sign in linear part of variational problem (varf vs problem)

**URL:** <https://community.freefem.org/t/change-of-sign-in-linear-part-of-variational-problem-varf-vs-problem/2984>\
**Category:** General Discussion\
**Created:** [February 22, 2024, 12:48pm UTC](https://community.freefem.org/t/change-of-sign-in-linear-part-of-variational-problem-varf-vs-problem/2984 "2024-02-22T12:48:50Z")\
**Posts on this page:** 1\
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**Author:** ![prj](https://avatars.discourse-cdn.com/v4/letter/p/ecae2f/32.png) [@prj](https://community.freefem.org/u/prj)\
**Post date:** [February 22, 2024, 1:19pm UTC](https://community.freefem.org/t/change-of-sign-in-linear-part-of-variational-problem-varf-vs-problem/2984/2 "2024-02-22T13:19:29Z")

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`solve vSolve(u, v) = a(u, v) + l(v)` solves `a(u, v) + l(v) = 0` while `varf vPb(u, v) = a(u, v) + l(v)` solves `a(u, v) = l(v)`, so it is expected that you need to shift the sign in front of the linear form.

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