ON THE h-VECTORS OF CHESSBOARD COMPLEXES

1 8 N ov 2 00 9 Chessboard complexes indomitable ∗

We give an alternative proof of the striking new Tverberg type theorem of Blagojević and Ziegler [B-Z]. Our method also yields some new cases of “constrained Tverberg thereom” in the sense of Hell [H], including a simple colored Radon’s theorem for d + 3 points in R (Corollary 7). This gives us an opportunity to review some of the highlights and reexamine the role of chessboard complexes in the...

Cycle-free chessboard complexes and symmetric homology of algebras

Chessboard complexes and their relatives have been an important recurring theme of topological combinatorics (see [1], [5], [10], [11], [13], [14], [20], [23], [24], [25]). Closely related “cycle-free chessboard complexes” have been recently introduced by Ault and Fiedorowicz in [2] and [9] as a tool for computing symmetric analogues of the cyclic homology of algebras. We study connectivity pro...

Chessboard Complexes and Matching Complexes

Theoretical Investigation of Interaction between 5-Fluorouracil Anticancer Drug with Various Nitrosamine Compounds

We present detailed theoretical studies of the H-bonded complexes formed from interaction between 5-fluorouracil and various six-membered cyclic nitrosamine compounds. In this study, an investigation on intermolecular interactions in X-NU (X = CH2, SiH2,BH, AlH, NH, PH, O and S) complexes is carried out using density functional theory. The calculations are conducted on B3L...

The clique operator on matching and chessboard graphs

Given positive integers m, n, we consider the graphs Gn and Gm,n whose simplicial complexes of complete subgraphs are the well-known matching complex Mn and chessboard complex Mm,n. Those are the matching and chessboard graphs. We determine which matching and chessboard graphs are clique-Helly. If the parameters are small enough, we show that these graphs (even if not clique-Helly) are homotopy...