Quasi relative interior

In topology, a branch of mathematics, the quasi-relative interior of a subset of a vector space is a refinement of the concept of the interior. Formally, if X is a linear space then the quasi-relative interior of A ⊆ X is

where c o n e ¯ ⁡ ( ⋅ ) denotes the closure of the conic hull.

Let X is a normed vector space, if C ⊂ X is a convex finite-dimensional set then qri ⁡ ( C ) = ri ⁡ ( C ) such that ri is the relative interior.