Let G be a group and D be a subgroup of G. In this paper we are interested in the description of the lattice L(D; G) = fH j D H Gg of subgroups of G which contain D. We call subgroups H 2 L(D; G) subgroups intermediate between D and G. We are primarily interested in the parametrization of intermediate subgroups and their behaviour with respect to set-theoretic and group-theoretic operations lik...

A circuit complexity of a graph is the minimum number of union and intersection operations needed to obtain the whole set of its edges starting from stars. Our main motivation to study this measure of graphs is that it is related to the circuit complexity of boolean functions. We prove some lower bounds to the circuit complexity of explicitly given graphs. In particular, we use the graph theore...

In this paper we construct evaluation codes on zero-dimensional complete intersections in toric varieties and give lower bounds for their minimum distance. This generalizes the results of Gold–Little–Schenck and Ballico–Fontanari who considered evaluation codes on complete intersections in the projective space.

The seminal complete intersection theorem of Ahlswede and Khachatrian gives the maximum cardinality of a k-uniform t-intersecting family on n points, and describes all optimal families. In recent work, we extended this theorem to the weighted setting, giving the maximum μp measure of a t-intersecting family on n points. In this work, we prove two new complete intersection theorems. The first gi...

A tropical complete intersection curve C ⊆ Rn+1 is a transversal intersection of n smooth tropical hypersurfaces. We give a formula for the number of vertices of C given by the degrees of the tropical hypersurfaces. We also compute the genus of C (defined as the number of independent cycles of C) when C is smooth and connected. 1 Notation and definitions We work over the tropical semifield Rtr=...

Complexity results are obtained with regard to problems of finding solutions to set of linear inequalities which are compatible with some set-functions and a prescribed intersection graph. It is shown that the additive case is SP-complete, the superadditive case is coSP-complete, and the subadditive case is in P. 0 1 1 Finding Addit,ive, Superaddit.ive and Subadditive Set-Functions Subject to L...