*Definition [#jf5af2fa]
A subset S of a topological space X is called semipreopen iff &ref(http://www.eaflux.com/imgtex/imgtex.fcgi?%5bres=100%5d%7b$%5cmathrm%7bcl%7d%28%5cmathrm%7bint%7d%28%5cmathrm%7bcl%7d%28S%29%29%29$%7d%25.png);.

*Reference [#s1270b5c]
-D. Andrijevic, ''Semi–preopen sets'', Mat. Vesnik 38 (1) (1986), 24–32.
-M. Ganster, ''Some remarks on strongly compact spaces and semi compact spaces'', Bull. Malaysian Math. Soc. (10) 2 (1987), 67–81.