# having fe spaces (of lower dimension) defined on sub-domains

Registered by Shawn W. Walker

It would be nice to have finite element spaces that are defined on specific sub-domains of a mesh. For example, having a lagrange multiplier space that is only defined on the boundary of the domain would be useful for some mixed formulations.

## Blueprint information

Status:
Complete
Approver:
None
Priority:
Medium
Drafter:
None
Direction:
Needs approval
Assignee:
None
Definition:
Superseded
Series goal:
None
Implementation:
Unknown
Milestone target:
None
Completed by
Marie Rognes

### Whiteboard

This Blueprint is related to discussion in the following Question:

We might also consider this Blueprint in light of the the Constrained Spaces for DirichletBC:

as we probably need similar interface changes.

MER: There is another blueprint on this, superseding this one.

(?)

### Work Items

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Everyone can see this information.