# \#inequalities **URL:** https://fenicsproject.discourse.group/tag/inequalities/63.md [Latest](https://fenicsproject.discourse.group/latest.md) · [Categories](https://fenicsproject.discourse.group/categories.md) · [Tags](https://fenicsproject.discourse.group/tags.md) --- ## [Adding bounds to a phase field problem](https://fenicsproject.discourse.group/t/adding-bounds-to-a-phase-field-problem/18381)
**Author:** [@M\_Saad](https://fenicsproject.discourse.group/u/M_Saad)\ **Replies:** 12\ **Last updated:** [November 29, 2025, 8:24am UTC](https://fenicsproject.discourse.group/t/adding-bounds-to-a-phase-field-problem/18381 "2025-11-29T08:24:27Z")
Hi! I am trying to implement a monolithic solver with energy based line search for a phase field ductile fracture model. The weak forms of the problem are: V = fem.functionspace(dmesh, (“Lagrange”, 1, (3,))) Q = fem.f…