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Tesi etd-09132011-145916


Thesis type
Tesi di laurea magistrale
Author
CARACENI, ALESSANDRA
URN
etd-09132011-145916
Title
Lagrangians of Hypergraphs
Struttura
SCIENZE MATEMATICHE, FISICHE E NATURALI
Corso di studi
MATEMATICA
Commissione
controrelatore Prof. Gaiffi, Giovanni
relatore Prof. Dvornicich, Roberto
Parole chiave
  • hypergraph lagrangian
  • graph
  • hypergraph
  • combinatorics
  • extremal graph theory
  • Turan problem
Data inizio appello
30/09/2011;
Consultabilità
completa
Riassunto analitico
The Lagrangian of a hypergraph is a function that in a sense seems to measure how ‘tightly packed’ a subset of the hypergraph one can find. Lagrangians were first used by Motzkin and Straus to obtain a new proof of a classic theorem of Turán, and subsequently found a number of very valuable applications in Extremal Hypergraph Theory; one remarkable result they yield is the disproof of a famous "jumping conjecture" of Erdos, which we reprove entirely; we will also introduce a very recent method based on Razborov's flag algebras to show that, though the jumping conjecture is false in general, hypergraphs "do jump" in some cases.
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