finitary matroid
1Matroid — In combinatorics, a branch of mathematics, a matroid (  /ˈmeɪ …
2Pregeometry (model theory) — Pregeometry, and in full combinatorial pregeometry, are essentially synonyms for matroid . They were introduced by G. C. Rota with the intention of providing a less ineffably cacaphonous alternative term. Also, the term combinatorial geometry,… …
3Pregeometry — In mathematics and physics, pregeometry has several meanings:* In combinatorics and most other mathematics, a matroid (as an abbreviation of combinatorial pregeometry ) * Pregeometry (model theory), a finitary matroid (as an abbreviation of… …
4Closure operator — In mathematics, a closure operator on a set S is a function cl: P(S) → P(S) from the power set of S to itself which satisfies the following conditions for all sets X,Y ⊆ S. X ⊆ cl(X) (cl is extensive) X ⊆ Y implies cl(X) ⊆ cl(Y)   (cl… …
