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JCT
2008
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13 years 4 months ago
Quadruple systems with independent neighborhoods
A 4-graph is odd if its vertex set can be partitioned into two sets so that every edge intersects both parts in an odd number of points. Let b(n) = max n 3 + (n - ) 3 = 1 2 + o...
Zoltán Füredi, Dhruv Mubayi, Oleg Pikh...
EJC
2006
13 years 4 months ago
Parity reversing involutions on plane trees and 2-Motzkin paths
The problem of counting plane trees with n edges and an even or an odd number of leaves has been recently studied by Eu, Liu and Yeh, in connection with an identity on coloring ne...
William Y. C. Chen, Louis W. Shapiro, Laura L. M. ...
GD
2007
Springer
13 years 11 months ago
Crossing Numbers and Parameterized Complexity
The odd crossing number of G is the smallest number of pairs of edges that cross an odd number of times in any drawing of G. We show that there always is a drawing realizing the o...
Michael J. Pelsmajer, Marcus Schaefer, Daniel Stef...