A következő kombinatorika szeminárium ideje
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    április 24. (péntek), 10:40 (a pesti vonat érkezése szerint kerekítve)
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helye
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                      Riesz terem
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Az előadás:

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Füredi Zoltán (Rényi Intézet):
   <B>Zykov's symmetrization for multiple graphs,
   a new tool for Turán type problems  with an application to
   Erdős' conjecture on pentagonal edges</B>
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Abstract: Erdős, Faudree, and Rousseau (1992) showed that a graph
on $n$ vertices and at least  $\lfloor n^2/4\rfloor+1$  edges
has at least $2\lfloor n/2\rfloor+1$ edges on triangles.
This result is sharp, just add an extra edge to the complete
bipartite graph.

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In this talk, we give an asymptotic formula for the minimum
number of edges contained on triangles in a graph having $n$
vertices and $e$ edges.

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The main tool of the proof is a
generalization of Zykov's symmetrization that  can be applied
for several graphs simultaneously.
We apply our weighted symmetrization method to tackle Erdős'
conjecture concerning the minimum number of edges on 5-cycles.

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Joint work with Zeinab Maleki (Isfahan).

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Minden érdeklődőt szeretettel várunk,

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Péter

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Supported by 
TÁMOP-4.2.2.A-11/1/KONV-2012-0073 projekt,
"Telemedicina fókuszú kutatások Orvosi, 
Matematikai és Informatikai tudományterületeken"