Eran Nevo
On Commensurizer Growth.
Пнд, 11/09/2009 - 16:01 — SomNambulAuthors: Eran Nevo, Nir Avni, Seonhee Lim
Subjects: Group Theory
AbstractWe study new asymptotic invariant of a pair consisting of a group and a
subgroup, which we call Commensurizer Growth. We compute the commensurizer
growth for several examples, concentrating mainly on the case of a locally
compact topological group and a lattice inside it.Regularity via topology of the lcm-lattice for $C_4$-free graphs.
Ср, 09/16/2009 - 13:15 — SomNambulAuthors: Eran Nevo
Subjects: Combinatorics
AbstractWe study the topology of the lcm-lattice of edge ideals and derive upper
bounds on the Castelnuovo-Mumford regularity of the ideals. In this context it
is natural to restrict to the family of graphs with no induced 4-cycle in their
complement. Using the above method we obtain sharp upper bounds on the
regularity when the complement is a chordal graph, or a cycle, or when the
primal graph is claw free with no induced 4-cycle in its complement. For the
later family we show that the second power of the edge ideal has a linear
resolution.Regularity via topology of the lcm-lattice for $C_4$-free graphs.
Ср, 09/16/2009 - 13:15 — SomNambulAuthors: Eran Nevo
Subjects: Combinatorics
AbstractWe study the topology of the lcm-lattice of edge ideals and derive upper
bounds on the Castelnuovo-Mumford regularity of the ideals. In this context it
is natural to restrict to the family of graphs with no induced 4-cycle in their
complement. Using the above method we obtain sharp upper bounds on the
regularity when the complement is a chordal graph, or a cycle, or when the
primal graph is claw free with no induced 4-cycle in its complement. For the
later family we show that the second power of the edge ideal has a linear
resolution.On $\gamma$-vectors satisfying the Kruskal-Katona inequalities.
Пт, 09/04/2009 - 12:10 — SomNambulAuthors: Eran Nevo, T. Kyle Petersen
Subjects: Combinatorics
AbstractWe present examples of flag homology spheres whose $\gamma$-vectors satisfy
the Kruskal-Katona inequalities. This includes several families of well-studied
simplicial complexes, including Coxeter complexes and the simplicial complexes
dual to the associahedron and to the cyclohedron. In another direction, we show
that if a flag $(d-1)$-sphere has at most $2d+2$ vertices its $\gamma$-vector
satisfies the Kruskal-Katona inequalities. We conjecture that if $\Delta$ is a
flag homology sphere then $\gamma(\Delta)$ satisfies the Kruskal-Katona
inequalities.- Читать далее
- login or register to post comments
Вход в систему
