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We provide a new tableau model from which one can easily deduce the characters of finite-dimensional irreducible polynomial representations of the special orthogonal group $SO_n(\mathbb{C})$. This model originates from the representation…

Combinatorics · Mathematics 2023-02-17 Hideya Watanabe

Let k>2. We prove that the cotangent bundles of oriented homotopy (2k-1)-spheres S and S' are symplectomorphic only if the classes defined by S and S' agree up to sign in the quotient group of oriented homotopy spheres modulo those which…

Symplectic Geometry · Mathematics 2015-09-21 Tobias Ekholm , Thomas Kragh , Ivan Smith

A matroid is Ingleton if all quadruples of subsets of its ground set satisfy Ingleton's inequality. In particular, representable matroids are Ingleton. We show that the number of Ingleton matroids on ground set $[n]$ is doubly exponential…

Combinatorics · Mathematics 2017-10-06 Peter Nelson , Jorn van der Pol

This paper highlights the similarities between even-dimensional geometry (symplectic) and odd-dimensional geometry (cosymplectic). We study the Lagrangian Grassmannian in the cosymplectic setting. The space of compatible co-complex…

Differential Geometry · Mathematics 2025-01-16 S. Tchuiaga , F. Balibuno , E. Djoukeng

Symplectic vector spaces are the phase spaces of linear mechanical systems. The symplectic form describes, for example, the relation between position and momentum as well as current and voltage. The category of linear Lagrangian relations…

Logic in Computer Science · Computer Science 2022-11-04 Cole Comfort , Aleks Kissinger

Swartz proved that any matroid can be realized as the intersection lattice of an arrangement of codimension one homotopy spheres on a sphere. This was an unexpected extension from the oriented matroid case, but unfortunately the…

Combinatorics · Mathematics 2015-03-13 Alexander Engstrom

We are interested in expanding our understanding of symplectic matroids by exploring the properties of a class of symplectic matroids with a "lattice of flats". Taking a well-behaved family of subdivisions of the cross polytope we obtain a…

Combinatorics · Mathematics 2026-01-08 Or Raz

The aim of the paper is to clarify the nature of combinatorial structures associated with maps on closed compact surfaces. We prove that maps give rise to Lagrangian matroids representable in a setting provided by cohomology of the surface…

Combinatorics · Mathematics 2007-05-23 Richard F. Booth , Alexandre V. Borovik , Israel Gelfand

We construct new examples of special Lagrangian submanifolds $Y\subset \mathbf{C}^{n+1}$, $n\geq 3$ in a neighborhood of the origin, with an isolated singularity, but with cylindrical tangent cone $C\times\mathbf{R}$. Moreover,…

Differential Geometry · Mathematics 2026-04-24 Guoran Ye

We prove that shifted cotangent stacks carry a canonical shifted symplectic structure. We also prove that shifted conormal stacks carry a canonical Lagrangian structure. These results were believed to be true but no written proof was…

Algebraic Geometry · Mathematics 2019-04-10 Damien Calaque

This paper contains a thorough introduction to the basic geometric properties of the manifold of Lagrangian subspaces of a linear symplectic space, known as the Lagrangian Grassmannian. It also reviews the important relationship between…

Differential Geometry · Mathematics 2019-02-26 Jan Gutt , Gianni Manno , Giovanni Moreno

We found some Lagrangian submanifolds of the adjoint semisimple orbit in two cases. For the first, the compact case, also known as the Generalized flag manifolds, we prove that the real flags can be seen as infinitesimally tight Lagrangian…

Symplectic Geometry · Mathematics 2026-01-16 Jhoan Baez , Luiz A. B. San Martin

A Formal Orthogonal Pair is a pair $(A,B)$ of symbolic rectangular matrices such that $AB^T=0$. It can be applied for the construction of Hadamard and Weighing matrices. In this paper we introduce a systematic way for constructing such…

Combinatorics · Mathematics 2020-06-03 Assaf Goldberger , Ilias Kotsireas

We generalize Baker-Bowler's theory of matroids over tracts to orthogonal matroids, define orthogonal matroids with coefficients in tracts in terms of Wick functions, orthogonal signatures, circuit sets, and orthogonal vector sets, and…

Combinatorics · Mathematics 2025-08-13 Tong Jin , Donggyu Kim

We initiate the study of a type $C_n$ generalization of the lattice path matroids defined by Bonin, de Mier, and Noy. These are delta matroids whose feasible sets are in bijection with lattice paths which are symmetric along the main…

Combinatorics · Mathematics 2023-11-28 Douglas M. Chen , Mario Sanchez , John Veliz , Zhiyan Ying

We study exotic Lagrangian tori in dimension four. In certain Stein domains $B_{dpq}$ (which naturally appear in almost toric fibrations) we find $d+1$ families of monotone Lagrangian tori which are mutually distinct, up to…

Symplectic Geometry · Mathematics 2024-10-10 Joé Brendel , Johannes Hauber , Joel Schmitz

Flag matroids are a rich family of Coxeter matroids that can be characterized using pairs of matroids that form a quotient. We consider a class of matroids called positroids, introduced by Postnikov, and utilize their combinatorial…

Combinatorics · Mathematics 2019-12-17 Carolina Benedetti , Anastasia Chavez , Daniel Tamayo

Consider the complex linear space C^n endowed with the canonical pseudo-Hermitian form of signature (2p,2(n-p)). This yields both a pseudo-Riemannian and a symplectic structure on C^n. We prove that those submanifolds which are both…

Differential Geometry · Mathematics 2012-02-08 Henri Anciaux

This paper investigates the question of uniqueness of the reduced oriented matroid structure arising from root systems of a Coxeter group in real vector spaces. We settle the question for finite Coxeter groups, irreducible affine Weyl…

Representation Theory · Mathematics 2017-10-12 Matthew Dyer , Weijia Wang

In this paper we first give a Bonnet theorem for conformal Lagrangian surfaces in complex space forms, then we show that any compact Lagrangian surface in the complex space form admits at most one other global isometric Lagrangian surface…

Differential Geometry · Mathematics 2015-03-31 Huixia He , Hui Ma , Erxiao Wang