# Lusternik–Schnirelmann category

> integer-valued homotopy invariant of spaces; the size of the minimal open cover consisting of contractible sets

**Wikidata**: [Q2361277](https://www.wikidata.org/wiki/Q2361277)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Lusternik–Schnirelmann_category)  
**Source**: https://4ort.xyz/entity/lusternik-schnirelmann-category


## References

1. Freebase Data Dumps. 2013