# Sitting instants

## Idea

A function or differential form on a manifold with boundary to a is said to have sitting instants at the boundary if there is an open neighbourhood $\partial X \subset U \subset X$ of the boundary such that the restriction $f|_U$ of $f$ to that neighbourhood is locally constant? in the direction perpendicular to the boundary.

## References

Last revised on July 23, 2018 at 14:48:58. See the history of this page for a list of all contributions to it.