The Experts below are selected from a list of 44928 Experts worldwide ranked by ideXlab platform

W. Tecumseh Fitch - One of the best experts on this subject based on the ideXlab platform.

  • Segmental Structure in banded mongoose calls
    BMC Biology, 2012
    Co-Authors: W. Tecumseh Fitch
    Abstract:

    In complex animal vocalizations, such as bird or whale song, a great variety of songs can be produced via rearrangements of a smaller set of 'syllables', known as 'phonological syntax' or 'phonocoding' However, food or alarm calls, which function as referential signals, were previously thought to lack such Combinatorial Structure. A new study of calls in the banded mongoose Mungos mungo provides the first evidence of phonocoding at the level of single calls. The first portion of the call provides cues to the identity of the caller, and the second part encodes its current activity. This provides the first example known in animals of something akin to the consonants and vowels of human speech.

Vallentin Frank - One of the best experts on this subject based on the ideXlab platform.

  • A polynomial time algorithm for solving the closest vector problem in zonotopal lattices
    'Society for Industrial & Applied Mathematics (SIAM)', 2021
    Co-Authors: Mccormick S. Thomas, Peis Britta, Scheidweiler Robert, Vallentin Frank
    Abstract:

    In this note we give a polynomial time algorithm for solving the closest vector problem in the class of zonotopal lattices. The Voronoi cell of a zonotopal lattice is a zonotope, i.e. a projection of a regular cube. Examples of zonotopal lattices include lattices of Voronoi's first kind and tensor products of root lattices of type A. The Combinatorial Structure of zonotopal lattices can be described by regular matroids/totally unimodular matrices. We observe that a linear algebra version of the minimum mean cycle canceling method can be applied for efficiently solving the closest vector problem in a zonotopal lattice if the lattice is given as the integral kernel of a totally unimodular matrix.Comment: 12 pages, v3: Comments of referees incorporated, to appear in SIAM Journal on Discrete Mathematics (SIDMA

  • A polynomial time algorithm for solving the closest vector problem in zonotopal lattices
    2020
    Co-Authors: Mccormick S. Thomas, Peis Britta, Scheidweiler Robert, Vallentin Frank
    Abstract:

    In this note we give a polynomial time algorithm for solving the closest vector problem in the class of zonotopal lattices. Zonotopal lattices are characterized by the fact that their Voronoi cell is a zonotope, i.e. a projection of a regular cube. Examples of zonotopal lattices include lattices of Voronoi's first kind and tensor products of root lattices of type A. The Combinatorial Structure of zonotopal lattices can be described by regular matroids/totally unimodular matrices. We observe that a linear algebra version of the minimum mean cycling canceling method can be applied for efficiently solving the closest vector problem in zonotopal lattices.Comment: 11 page

Sattelberger Anna-laura - One of the best experts on this subject based on the ideXlab platform.

  • Algebraic Analysis of the Hypergeometric Function 1F1 of a Matrix Argument
    2020
    Co-Authors: Görlach Paul, Lehn Christian, Sattelberger Anna-laura
    Abstract:

    In this article, we investigate Muirhead's classical system of differential operators for the hypergeometric function 1F1 of a matrix argument. We formulate a conjecture for the Combinatorial Structure of the characteristic variety of its Weyl closure which is both supported by computational evidence as well as theoretical considerations. In particular, we determine the singular locus of this system.Comment: 22 page

  • Algebraic Analysis of the Hypergeometric Function 1F1 of a Matrix Argument
    'Springer Science and Business Media LLC', 2020
    Co-Authors: Görlach Paul, Lehn Christian, Sattelberger Anna-laura
    Abstract:

    In this article, we investigate Muirhead's classical system of differential operators for the hypergeometric function 1F1 of a matrix argument. We formulate a conjecture for the Combinatorial Structure of the characteristic variety of its Weyl closure which is both supported by computational evidence as well as theoretical considerations. In particular, we determine the singular locus of this system.Comment: 26 pages. v2 changes: included Appendix discussing the singular locus for degenerate parameter

Nathaniel Thiem - One of the best experts on this subject based on the ideXlab platform.

  • branching rules in the ring of superclass functions of unipotent upper triangular matrices
    Discrete Mathematics & Theoretical Computer Science, 2009
    Co-Authors: Nathaniel Thiem
    Abstract:

    It is becoming increasingly clear that the supercharacter theory of the finite group of unipotent upper-triangular matrices has a rich Combinatorial Structure built on set-partitions that is analogous to the partition combinatorics of the classical representation theory of the symmetric group. This paper begins by exploring a connection to the ring of symmetric functions in non-commuting variables that mirrors the symmetric group's relationship with the ring of symmetric functions. It then also investigates some of the representation theoretic Structure constants arising from the restriction, tensor products and superinduction of supercharacters.

  • branching rules in the ring of superclass functions of unipotent upper triangular matrices
    arXiv: Representation Theory, 2008
    Co-Authors: Nathaniel Thiem
    Abstract:

    It is becoming increasingly clear that the supercharacter theory of the finite group of unipotent upper-triangular matrices has a rich Combinatorial Structure built on set-partitions that is analogous to the partition combinatorics of the classical representation theory of the symmetric group. This paper begins by exploring a connection to the ring of symmetric functions in non-commuting variables that mirrors the symmetric group's relationship with the ring of symmetric functions. It then also investigates some of the representation theoretic Structure constants arising from the restriction, tensor products and superinduction of supercharacters in this context.

Nicholas D Sidiropoulos - One of the best experts on this subject based on the ideXlab platform.

  • fast optimization of boolean quadratic functions via iterative submodular approximation and max flow
    International Conference on Acoustics Speech and Signal Processing, 2019
    Co-Authors: Aritra Konar, Nicholas D Sidiropoulos
    Abstract:

    We consider the NP–hard Combinatorial optimization problem of minimizing arbitrary quadratic forms over the {0, 1 } (Boolean) lattice. While polynomial-time approximation algorithms do exist for such problems, they suffer from the practical drawback of being computationally involved – often a side effect of being agnostic to the Combinatorial Structure inherent in the problem. In this paper, we propose a computationally lightweight approximation alternative which specifically exploits the Combinatorial Structure of the problem. The key result underlying our approach is that any Boolean quadratic function can be expressed as a difference of quadratic sub-modular functions, which enables us to construct and iteratively min-imize a sequence of global submodular upper bounds on the cost function. This entails solving a quadratic submodular function min-imization problem at each step, which can be efficiently accomplished via the seminal Max-Flow algorithm. Overall, our algorithm performs iterative approximation by solving a sequence of maximum-flow problems. The merits of using this approach are illustrated via simulations which indicate the very favorable performance of our algorithm.