SageMath: research and experimentation in Combinatorics - Lecture 1
By Viviane Pons
SageMath: research and experimentation in Combinatorics - Lecture 2
By Viviane Pons
Appears in collection : Combinatorial geometries: matroids, oriented matroids and applications / Géométries combinatoires : matroïdes, matroïdes orientés et applications
A cube is a matroid over $C^n={-1,+1}^n$ that contains as circuits the usual rectangles of the real affine cube packed in such a way that the usual facets and skew-facets are hyperplanes of the matroid. How many cubes are orientable? So far, only one: the oriented real affine cube. We review the results obtained so far concerning this question. They follow two directions: 1)Identification of general obstructions to orientability in this class. (da Silva, EJC 30 (8), 2009, 1825-1832). 2)(work in collaboration with E. Gioan) Identification of algebraic and geometric properties of recursive families of non-negative integer vectors defining hyperplanes of the real affine cube and the analysis of this question and of las Vergnas cube conjecture in small dimensions.