# What does the degree symbol in $K_n \subset K_{n+1}^{\circ}$ mean?

What does the degree symbol in "Let $(K_n)$ be a sequence of compact subsets such that $K_n \subset K_{n+1}^{\circ}$ mean?

-
Almost certainly, "interior". – Arturo Magidin May 6 '12 at 23:40
The interior of the set. – David Mitra May 6 '12 at 23:41
@ArturoMagidin You or David should post this as an answer so that the asker can accept it. – Alex Becker May 7 '12 at 0:20