I worked this theory : https://mathoverflow.net/questions/317668/a-new-generalization-of-the-dimension For have a theorem of the dimension, and be more generaler and simpler than the Matroïds. > **Definition 1:** A structure $S$, is a pair $(X, \mathcal T)$ with $X$ a set and $\mathcal T$ a set of subsets of $X$, stable by arbitrary intersections, with $X \in \mathcal T$. > > **Definition 2:** Let $U \subset X$ we denote >$\langle U\rangle_S=\bigcap \limits_{F \in \mathcal T, U \subset F} F$ > >**Definition 3:** $S=(X,\mathcal T)$ a structure, we say the set $U\neq \emptyset$ is free if : > $\forall u \in U, u \notin \langle v \mid v \in U,v\neq u \rangle_S$ > > **Definition 4:** $S=(X,\mathcal T)$ a structure, we say this structur have a dimension if: >$\forall U \subset X$ free, with $v \notin \langle U\rangle$, $U \cup \{v\}$ is free. > > **Definition 5:** $S=(X,\mathcal T)$ a structure, $F \in \mathcal T$, we note $\dim(F)=n$ if: >the largest free set of $F$ have a cardinal of $n$. > > **Theorem:** $S=(X,\mathcal T)$ a structure with a dimension, $E,F \in \mathcal T$, > if $\dim(E)=\dim(F)<\infty$ and $E \subset F$ then $E=F$ > *Question: Is this generalization of the dimension already existing?*