Title of article :
An extended lower bound on the number of -edges to generalized configurations of points and the pseudolinear crossing number of
Author/Authors :
ءbrego، نويسنده , , B.M. and Balogh، نويسنده , , J. and Fernلndez-Merchant، نويسنده , , S. and Leaٌos، نويسنده , , J. and Salazar، نويسنده , , G.، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2008
Pages :
8
From page :
1257
To page :
1264
Abstract :
Recently, Aichholzer, García, Orden, and Ramos derived a remarkably improved lower bound for the number of ( ⩽ k ) -edges in an n-point set, and as an immediate corollary, an improved lower bound on the rectilinear crossing number of K n . We use simple allowable sequences to extend all their results to the more general setting of simple generalized configurations of points and slightly improve the lower bound on Sylvesterʹs constant from 0.37963 to 0.379688. In other words, we prove that the pseudolinear (and consequently the rectilinear) crossing number of K n is at least 0.379688 ( n 4 ) + Θ ( n 3 ) . We use this to determine the exact pseudolinear crossing numbers of K n and the maximum number of halving pseudolines in an n-point set for n = 10 , 11 , 12 , 13 , 15 , 17 , 19 , and 21. All these values coincide with the corresponding rectilinear numbers obtained by Aichholzer et al.
Keywords :
pseudolinear crossing number , Complete graphs , Halving lines , Halving pseudolines , rectilinear crossing number , k-edges , Allowable sequences
Journal title :
Journal of Combinatorial Theory Series A
Serial Year :
2008
Journal title :
Journal of Combinatorial Theory Series A
Record number :
1531333
Link To Document :
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