Lagrangian pairs and Lagrangian orthogonal matroids
نویسندگان
چکیده
منابع مشابه
Lagrangian pairs and Lagrangian orthogonal matroids
Represented Coxeter matroids of types Cn and Dn, that is, symplectic and orthogonal matroids arising from totally isotropic subspaces of symplectic or (even-dimensional) orthogonal spaces, may also be represented in buildings of type Cn and Dn, respectively (see [4, Chapter 7]). Indeed, the particular buildings involved are those arising from the flags or oriflammes, respectively, of totally is...
متن کاملLagrangian Matroids and Cohomology
We prove that ∆-matroids associated with maps on compact closed surfaces are representable, with the space of representation provided by cohomology of the surface with punctured points.
متن کاملOriented Lagrangian Matroids
The aim of this paper is to develop, by analogy with the theory of oriented (ordinary) matroids [2], an oriented version of the theory of Lagrangian symplectic matroids [7]. Recall that the concept of an oriented matroid axiomatises, in combinatorial form, the properties of the ensemble of non-zero k× k minors of a real k× n matrix A, say. The k-subsets of indices of columns of A such that the ...
متن کاملLagrangian Matroids: Representations of Type Bn
Coxeter matroids are combinatorial objects associated with finite Coxeter groups; they can be viewed as subsets M of the factor set W/P of a Coxeter group W by a parabolic subgroup P which satisfy a certain maximality property with respect to a family of shifted Bruhat orders on W/P . The classical matroids of matroid theory are exactly the Coxeter matroids for the symmetric group Symn (which i...
متن کاملOriented Lagrangian Orthogonal Matroid Representations
Several attempts have been made to extend the theory of matroids (here referred to as ordinary or classical matroids) to theories of more general objects, in particular the Coxeter matroids of Borovik, Gelfand and White ([7], first introduced as WP-matroids in [10]), and the ∆-matroids and (equivalent but for notation) symmetric matroids of Bouchet (see, for example, [8]). The special cases of ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: European Journal of Combinatorics
سال: 2005
ISSN: 0195-6698
DOI: 10.1016/j.ejc.2004.06.016