Theorems in graph theory | Articles containing proofs | Ramsey theory
In combinatorics, Ramsey's theorem, in one of its graph-theoretic forms, states that one will find monochromatic cliques in any edge labelling (with colours) of a sufficiently large complete graph. To demonstrate the theorem for two colours (say, blue and red), let r and s be any two positive integers. Ramsey's theorem states that there exists a least positive integer R(r, s) for which every blue-red edge colouring of the complete graph on R(r, s) vertices contains a blue clique on r vertices or a red clique on s vertices. (Here R(r, s) signifies an integer that depends on both r and s.) Ramsey's theorem is a foundational result in combinatorics. The first version of this result was proved by F. P. Ramsey. This initiated the combinatorial theory now called Ramsey theory, that seeks regularity amid disorder: general conditions for the existence of substructures with regular properties. In this application it is a question of the existence of monochromatic subsets, that is, subsets of connected edges of just one colour. An extension of this theorem applies to any finite number of colours, rather than just two. More precisely, the theorem states that for any given number of colours, c, and any given integers n1, …, nc, there is a number, R(n1, …, nc), such that if the edges of a complete graph of order R(n1, …, nc) are coloured with c different colours, then for some i between 1 and c, it must contain a complete subgraph of order ni whose edges are all colour i. The special case above has c = 2 (and n1 = r and n2 = s). (Wikipedia).
Ramsey theory is based on Ramsey's theorem, because without it, there would be no Ramsey numbers, since they are not well-defined. This is part 2 of the trilogy of the Ramsey numbers. Useful link: https://en.wikipedia.org/wiki/Ramsey%27s_theorem#2-colour_case Other than commenting on the
From playlist Ramsey trilogy
Advances on Ramsey numbers - Jacob Fox
https://www.math.ias.edu/seminars/abstract?event=83564
From playlist Computer Science/Discrete Mathematics
This video is about some of the basic properties of Ramsey numbers.
From playlist Basics: Graph Theory
Ramsey theorems for classes of structures with (...) - J. Hubička - Workshop 1 - CEB T1 2018
Jan Hubička (Charles U) / 02.02.2018 Ramsey theorems for classes of structures with functions and relations We discuss a generalization of Nešetřil-Rődl theorem for free amalgamation classes of structures in a language containing both relations and partial functions. Then we further stre
From playlist 2018 - T1 - Model Theory, Combinatorics and Valued fields
Lie Algebra Representations Arising from Ramsey Theory
Speakers; Alejandro Buendia(Ramsey's Theorem, Computation of Lie Algebras, Irreducible Decomposition of Wr, Diagonal Ramsey numbers). Junho Won(Lie Algebras Background, Representation, Subgraph-Recoloring Operators, The Cases r = p, r = p+ 1, Simple subalgebras). Jia Wan( Representation
From playlist 2017 Summer REU Presentations
The Fundamental Theorem of Calculus | Algebraic Calculus One | Wild Egg
In this video we lay out the Fundamental Theorem of Calculus --from the point of view of the Algebraic Calculus. This key result, presented here for the very first time (!), shows how to generalize the Fundamental Formula of the Calculus which we presented a few videos ago, incorporating t
From playlist Algebraic Calculus One
Calculus - The Fundamental Theorem, Part 3
The Fundamental Theorem of Calculus. Specific examples of simple functions, and how the antiderivative of these functions relates to the area under the graph.
From playlist Calculus - The Fundamental Theorem of Calculus
Using nonstandard natural numbers in Ramsey Theory - M. Di Nasso - Workshop 1 - CEB T1 2018
Mauro Di Nasso (Pisa) / 01.02.2018 In Ramsey Theory, ultrafilters often play an instrumental role. By means of nonstandard models, one can reduce those third-order objects (ultrafilters are sets of sets of natural numbers) to simple points. In this talk we present a nonstandard technique
From playlist 2018 - T1 - Model Theory, Combinatorics and Valued fields
Metrizable universal minimal flows and Ramsey theory - T. Tsankov - Workshop 1 - CEB T1 2018
Todor Tsankov (Université Paris Diderot) / 01.02.2018 The connection between Ramsey theory and topological dynamics goes back at least to Furstenberg who used dynamical systems of the group of integers to derive a new proof of Van Der Waerden’s theorem. More recently, Kechris, Pestov, and
From playlist 2018 - T1 - Model Theory, Combinatorics and Valued fields
Natasha Dobrinen: Borel sets of Rado graphs are Ramsey
The Galvin-Prikry theorem states that Borel partitions of the Baire space are Ramsey. Thus, given any Borel subset $\chi$ of the Baire space and an infinite set $N$, there is an infinite subset $M$ of $N$ such that $\left [M \right ]^{\omega }$ is either contained in $\chi$ or disjoint fr
From playlist Combinatorics
Vitaly Bergelson: Mutually enriching connections between ergodic theory and combinatorics - part 6
Abstract : * The early results of Ramsey theory : Hilbert's irreducibility theorem, Dickson-Schur work on Fermat's equation over finite fields, van der Waerden's theorem, Ramsey's theoremand its rediscovery by Erdos and Szekeres. * Three main principles of Ramsey theory : First principl
From playlist Jean-Morlet Chair - Lemanczyk/Ferenczi
Vitaly Bergelson: Mutually enriching connections between ergodic theory and combinatorics - part 1
Abstract : * The early results of Ramsey theory : Hilbert's irreducibility theorem, Dickson-Schur work on Fermat's equation over finite fields, van der Waerden's theorem, Ramsey's theoremand its rediscovery by Erdos and Szekeres. * Three main principles of Ramsey theory : First principl
From playlist Jean-Morlet Chair - Lemanczyk/Ferenczi
Vitaly Bergelson: Mutually enriching connections between ergodic theory and combinatorics - part 7
Abstract : * The early results of Ramsey theory : Hilbert's irreducibility theorem, Dickson-Schur work on Fermat's equation over finite fields, van der Waerden's theorem, Ramsey's theoremand its rediscovery by Erdos and Szekeres. * Three main principles of Ramsey theory : First principl
From playlist Jean-Morlet Chair - Lemanczyk/Ferenczi
Vitaly Bergelson: Mutually enriching connections between ergodic theory and combinatorics - part 2
Abstract : * The early results of Ramsey theory : Hilbert's irreducibility theorem, Dickson-Schur work on Fermat's equation over finite fields, van der Waerden's theorem, Ramsey's theoremand its rediscovery by Erdos and Szekeres. * Three main principles of Ramsey theory : First principl
From playlist Jean-Morlet Chair - Lemanczyk/Ferenczi
Vitaly Bergelson: Mutually enriching connections between ergodic theory and combinatorics- part 4
Abstract : * The early results of Ramsey theory : Hilbert's irreducibility theorem, Dickson-Schur work on Fermat's equation over finite fields, van der Waerden's theorem, Ramsey's theoremand its rediscovery by Erdos and Szekeres. * Three main principles of Ramsey theory : First principl
From playlist Jean-Morlet Chair - Lemanczyk/Ferenczi
Vitaly Bergelson: Mutually enriching connections between ergodic theory and combinatorics - part 5
Abstract : * The early results of Ramsey theory : Hilbert's irreducibility theorem, Dickson-Schur work on Fermat's equation over finite fields, van der Waerden's theorem, Ramsey's theoremand its rediscovery by Erdos and Szekeres. * Three main principles of Ramsey theory : First principl
From playlist Jean-Morlet Chair - Lemanczyk/Ferenczi
Vitaly Bergelson: Mutually enriching connections between ergodic theory and combinatorics - part 3
Abstract : * The early results of Ramsey theory : Hilbert's irreducibility theorem, Dickson-Schur work on Fermat's equation over finite fields, van der Waerden's theorem, Ramsey's theoremand its rediscovery by Erdos and Szekeres. * Three main principles of Ramsey theory : First principl
From playlist Jean-Morlet Chair - Lemanczyk/Ferenczi
New Developments in Hypergraph Ramsey Theory - D. Mubayi - Workshop 1 - CEB T1 2018
Dhruv Mubayi (UI Chicago) / 30.01.2018 I will describe lower bounds (i.e. constructions) for several hypergraph Ramsey problems. These constructions settle old conjectures of Erd˝os–Hajnal on classical Ramsey numbers as well as more recent questions due to Conlon–Fox–Lee–Sudakov and othe
From playlist 2018 - T1 - Model Theory, Combinatorics and Valued fields
Extremal Combinatorics with Po-Shen Loh 03/30 Mon
Carnegie Mellon University is protecting the community from the COVID-19 pandemic by running courses online for the Spring 2020 semester. This is the video stream for Po-Shen Loh’s PhD-level course 21-738 Extremal Combinatorics. Professor Loh will not be able to respond to questions or com
From playlist CMU PhD-Level Course 21-738 Extremal Combinatorics
Multivariable Calculus | The Squeeze Theorem
We calculate a limit using a multivariable version of the squeeze theorem. http://www.michael-penn.net http://www.randolphcollege.edu/mathematics/
From playlist Multivariable Calculus