Commutative algebra | Algebraic combinatorics | Algebraic geometry
Combinatorial commutative algebra is a relatively new, rapidly developing mathematical discipline. As the name implies, it lies at the intersection of two more established fields, commutative algebra and combinatorics, and frequently uses methods of one to address problems arising in the other. Less obviously, polyhedral geometry plays a significant role. One of the milestones in the development of the subject was Richard Stanley's 1975 proof of the Upper Bound Conjecture for simplicial spheres, which was based on earlier work of Melvin Hochster and Gerald Reisner. While the problem can be formulated purely in geometric terms, the methods of the proof drew on commutative algebra techniques. A signature theorem in combinatorial commutative algebra is the characterization of h-vectors of simplicial polytopes conjectured in 1970 by Peter McMullen. Known as the g-theorem, it was proved in 1979 by Stanley (necessity of the conditions, algebraic argument) and by Louis Billera and Carl W. Lee (sufficiency, combinatorial and geometric construction). A major open question was the extension of this characterization from simplicial polytopes to simplicial spheres, the g-conjecture, which was resolved in 2018 by Karim Adiprasito. (Wikipedia).
A combinatorial approach to the determinant using permutations.
From playlist Linear Algebra
Commutative algebra 1 (Introduction)
This lecture is part of an online course on commutative algebra, following the book "Commutative algebra with a view toward algebraic geometry" by David Eisenbud. https://link.springer.com/book/10.1007/978-1-4612-5350-1 This is a short introductory lecture, and gives a few examples of the
From playlist Commutative algebra
Commutative algebra 2 (Rings, ideals, modules)
This lecture is part of an online course on commutative algebra, following the book "Commutative algebra with a view toward algebraic geometry" by David Eisenbud. This lecture is a review of rings, ideals, and modules, where we give a few examples of non-commutative rings and rings without
From playlist Commutative algebra
Commutative algebra 27 (Associated primes)
This lecture is part of an online course on commutative algebra, following the book "Commutative algebra with a view toward algebraic geometry" by David Eisenbud. We show that every finitely generated module M over a Noetherian ring R can broken up into modules of the form R/p for p prime
From playlist Commutative algebra
A more in depth discussion on the determinant of a square matrix.
From playlist Linear Algebra
Darij Grinberg -Quotients of Symmetric Polynomial Rings Deforming theCohomology of the Grassmannian
One of the many connections between Grassmannians and combinatorics is cohomological: The cohomology ring of a Grassmannian Gr(k,n) is a quotient of the ring S of symmetric polynomials in k variables. More precisely, it is the quotient of S by the ideal generated by the k consecutive compl
From playlist Combinatorics and Arithmetic for Physics: 02-03 December 2020
Commutative algebra 21 Tensor products and exactness
This lecture is part of an online course on commutative algebra, following the book "Commutative algebra with a view toward algebraic geometry" by David Eisenbud. In this lecture we study when taking tensor product preserves exactness. We also show that tensor products preserve direct lim
From playlist Commutative algebra
Frédéric Patras - Noncommutative Wick Polynomials
Wick polynomials are at the foundations of QFT (they encode normal orderings) and probability (they encode chaos decompositions). In this lecture, we survey the construction and properties of noncommutative (or free) analogs using shuffle Hopf algebra techniques. Based on joint works wit
From playlist Combinatorics and Arithmetic for Physics: special days
Loïc FOISSY - Cointeracting Bialgebras
Pairs of cointeracting bialgebras recently appears in the literature of combinatorial Hopf algebras, with examples based on formal series, on trees (Calaque, Ebrahimi-Fard, Manchon), graphs (Manchon), posets... We will give several results obtained on pairs of cointeracting bialgebras: act
From playlist Algebraic Structures in Perturbative Quantum Field Theory: a conference in honour of Dirk Kreimer's 60th birthday
Matt SZCZESNY - Toric Hall Algebras and infinite-dimentional Lie algebras
The process of counting extensions in categories yields an associative (and sometimes Hopf) algebra called a Hall algebra. Applied to the category of Feynman graphs, this process recovers the Connes-Kreimer Hopf algebra. Other examples abound, yielding various combinatorial Hopf algebras.
From playlist Algebraic Structures in Perturbative Quantum Field Theory: a conference in honour of Dirk Kreimer's 60th birthday
Kurusch EBRAHIMI-FARD - Wick Products and Combinatorial Hopf Algebras
Wick products play a central role in both quantum field theory and stochastic calculus. They originated in Wick’s work from 1950. In this talk we will describe Wick products using combinatorial Hopf algebra. Based on joint work with F. Patras, N. Tapia, L. Zambotti. https://indico.math.c
From playlist Algebraic Structures in Perturbative Quantum Field Theory: a conference in honour of Dirk Kreimer's 60th birthday
Ernesto Lupercio: On the moduli space for Quantum Toric Varieties
Talk by Ernesto Lupercio in Global Noncommutative Geometry Seminar (Americas) on November 5, 2021, https://globalncgseminar.org/talks/tba-17/
From playlist Global Noncommutative Geometry Seminar (Americas)
Nicolas Behr - Tracelet Algebras
Stochastic rewriting systems evolving over graph-like structures are a versatile modeling paradigm that covers in particular biochemical reaction systems. In fact, to date rewriting-based frameworks such as the Kappa platform [1] are amongst the very few known approaches to faithfully enco
From playlist Combinatorics and Arithmetic for Physics: 02-03 December 2020
Representations are sheaves' for Legendrian 2-weaves - Kevin Sackel
Joint IAS/Princeton University Symplectic Geometry Seminar Topic: Representations are sheaves' for Legendrian 2-weaves Speaker: Kevin Sackel Affiliation: Stony Brook University Date: March 21, 2022 Given a trivalent plane graph embedded in the Euclidean plane (up to isotopy), Treumann an
From playlist Mathematics
Bryna Kra : Multiple ergodic theorems: old and new - lecture 1
Abstract : The classic mean ergodic theorem has been extended in numerous ways: multiple averages, polynomial iterates, weighted averages, along with combinations of these extensions. I will give an overview of these advances and the different techniques that have been used, focusing on co
From playlist Dynamical Systems and Ordinary Differential Equations
5B Commutative Law of Matrix Multiplication-YouTube sharing.mov
A closer look at three examples of the Commutative Law of Matrix Multiplication.
From playlist Linear Algebra
Monica Vazirani: From representations of the rational Cherednik algebra to parabolic Hilbert schemes
Abstract: Young diagrams and standard tableaux on them parameterize irreducible representations of the symmetric group and their bases, respectively. There is a similar story for the double affine Hecke algebra (DAHA) taking periodic tableaux, or for the rational Cherednik algebra (a.k.a.
From playlist SMRI Algebra and Geometry Online
Nezhla Aghaei - Combinatorial Quantisation of Supergroup Chern-Simons Theory
Chern-Simons Theories with gauge super-groups appear naturally in string theory and they possess interesting applications in mathematics, e.g. for the construction of knot and link invariants. In my talk, I will review the framework of combinatorial quantization of Chern Simons theory and
From playlist Workshop on Quantum Geometry
Commutative algebra 54: Hilbert polynomials
This lecture is part of an online course on commutative algebra, following the book "Commutative algebra with a view toward algebraic geometry" by David Eisenbud. We define the Hilbert polynomial of a graded module over a graded Noetherian ring. Reading: Section Exercises:
From playlist Commutative algebra