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Best simultaneous diophantine approximations of some cubic algebraic numbers

Nicolas Chevallier (2002)

Journal de théorie des nombres de Bordeaux

Let α be a real algebraic number of degree 3 over whose conjugates are not real. There exists an unit ζ of the ring of integer of K = ( α ) for which it is possible to describe the set of all best approximation vectors of θ = ( ζ , ζ 2 ) .’

Bethe Ansatz and the geography of rigged strings

Tadeusz Lulek (2007)

Banach Center Publications

We demonstrate the way in which composition of two famous combinatorial bijections, of Robinson-Schensted and Kerov-Kirillov-Reshetikhin, applied to the Heisenberg model of magnetic ring with spin 1/2, defines the geography of rigged strings (which label exact eigenfunctions of the Bethe Ansatz) on the classical configuration space (the set of all positions of the system of r reversed spins). We point out that each l-string originates, in the language of this bijection, from an island of l consecutive...

Betti numbers of some circulant graphs

Mohsen Abdi Makvand, Amir Mousivand (2019)

Czechoslovak Mathematical Journal

Let o ( n ) be the greatest odd integer less than or equal to n . In this paper we provide explicit formulae to compute -graded Betti numbers of the circulant graphs C 2 n ( 1 , 2 , 3 , 5 , ... , o ( n ) ) . We do this by showing that this graph is the product (or join) of the cycle C n by itself, and computing Betti numbers of C n * C n . We also discuss whether such a graph (more generally, G * H ) is well-covered, Cohen-Macaulay, sequentially Cohen-Macaulay, Buchsbaum, or S 2 .

BG-ranks and 2-cores.

Chen, William Y.C., Ji, Kathy Q., Wilf, Herbert S. (2006)

The Electronic Journal of Combinatorics [electronic only]

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