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# Linear Algebra

**DMS Linear Algebra/Algebra Seminar**

Sep 25, 2018 04:00 PM

Parker Hall 354

Speaker: **Douglas A. Leonard**

Title: Using Computer Algebra Systems to improve mathematical theory

Abstract: Mathematicians seem adverse to putting examples in their research papers, higher level textbooks, or even course notes. (My intro to commutative algebra was a slick deﬁnition-theorem-proof course from which I learned nothing about the topic but something about proofs instead.) This is compounded when others write code to implement theory in some CAS (computer algebra system). Mathematical theory, can be wrong, misguided, too general, or too complicated. The code can be wrong, misguided, too general, or too complicated as well, even when the underlying math is at least not wrong. If one can work through reasonable examples of the theory (so non-trivial, but not hopelessly pathological) using a CAS, then one is forced to think very hard about programming each step. This can lead to alternative viewpoints and maybe even an overhauling of the theory. I’ll probably concentrate on resolving singularities, starting with the example described by \(y^3 + yx + x^5 = 0\), using Macaulay2 and/or Singular.

**DMS Linear Algebra/Algebra Seminar**

Sep 18, 2018 04:00 PM

Parker Hall 354

Speaker: **Wei Gao**

Title: Inertia sets allowed or required by matrix patterns

Abstract: A sign pattern matrix is a matrix whose entries come from the set \({+, -, 0}\). A zero-nonzero pattern matrix is a matrix with entries from \({*,0}\), where \(*\) is nonzero. Motivated by the possible onset of instability in dynamical systems, sign patterns and zero-nonzero patterns that allow or require some special sets of inertias and refined inertias are discussed in some papers. In this talk, some known results and techniques will be shown.

**DMS Linear Algebra/Algebra Seminar**

Sep 11, 2018 04:00 PM

Parker Hall 354

Speaker: **Sheng Bao**

Title: Metric spaces of abelian groups

Abstract: Metric spaces arise as Cayley graphs of groups. In the locally finite infinite case, not much is known. We consider metric spaces of vector groups (finitely generated torsion-free abelian groups) and propose some feasible questions about monotonicity of dimensions, finite resolution and bisectors while reporting on some beginning results on these.

**DMS Linear Algebra / Algebra Seminar**

Sep 04, 2018 04:00 PM

Parker Hall 354

Speaker: **Daryl Granario**

Title: The duality of the matrix transpose and conjugate-inverse maps

Abstract: Please click here

**DMS Linear Algebra / Algebra Seminar**

Aug 28, 2018 04:00 PM

Parker Hall 354

**ORGANIZATIONAL MEETING**

**DMS Linear Algebra/Algebra Seminar**

Apr 17, 2018 04:00 PM

Parker Hall 352

Speaker: **Tin-Yau Tam**

Title: Matrix Inequalities and Their Extensions to Lie Groups

Abstract: We will discuss some classical matrix inequalities and their extensions that are topics in my new book *Matrix Inequalities and Their Extensions to Lie Groups*.

**DMS Linear Algebra/Algebra Seminar**

Apr 03, 2018 04:00 PM

Parker Hall 352

Speaker: **Avantha Indika**

Title: A study of the structure of the symmetry classes

Abstract: Will discuss the studies on standard (decomposable) symmetrized tensors to understand the structure of symmetry classes of tensors associated with finite groups and the use of coset space to understand the geometric structure of a symmetry class of tensors.

**DMS Linear Algebra/Algebra Seminar**

Mar 20, 2018 04:00 PM

Speaker:

**Zejun Huang**(Hunan University, China)

Title: Preserver problems on matrices

Abstract: Preserver problems on matrices concern the characterization of linear or nonlinear maps on matrices that leave certain properties invariant. In this talk, I will present some results on both linear and nonlinear preserver problems on matrices.

**DMS Linear Algebra/Algebra Seminar**

Mar 06, 2018 04:00 PM

Parker Hall 352

Speaker:

**Jason Liu**

Title: Toeplitz Matrices, Symmetric Matrices, and Unitary Similarity

Abstract: In this talk, I will present the result that every Toeplitz matrix is uniformly unitarily similar to some complex symmetric matrices via a unitary matrix. Conversely, every symmetric matrix is unitarily similar to some Toeplitz matrix when \(n < 4\). I will relate this result with the facts of every matrix is a product of some Toeplitz matrices, which was proved by Ye and Lim in 2015, and a super-fast divide-and-conquer method to make the eigenproblem of Toeplitz matrices with nearly linear complexity presented by Vogel et al. in 2016. I will also present that every multilevel Toeplitz matrix is unitarily similar to a symmetric matrix.

**DMS Linear Algebra/Algebra Seminar**

Feb 27, 2018 04:00 PM

Parker Hall 352

Speaker: **Zhuoheng He**

Title: The general \(\phi\)-Hermitian solution to mixed pairs of quaternion matrix Sylvester equations

Abstract: In this talk, we consider two systems of mixed pairs of quaternion matrix Sylvester equations

\[A_{1}X-YB_{1}=C_{1},~A_{2}Z-YB_{2}=C_{2}\] and \[A_{1}X-YB_{1}=C_{1},~A_{2}Y-ZB_{2}=C_{2},\]

where \(Z\) is \(\phi\)-Hermitian. Some practical necessary and sufficient conditions for the existence of a solution \((X,Y,Z)\) to those systems in terms of the ranks and Moore-Penrose inverses of the given coefficient matrices will be presented. Moreover, the general solutions to these systems are explicitly given when they are solvable. We also provide some numerical examples to illustrate our results.

Last Updated: 08/21/2017