the present note arises from the author's talk at the conference ``ischia group theory 2014''. for subgroups $fle n$ of a group $g$ denote by $lat(f,n)$ the set of all subgroups of $n$, containing $f$. let $d$ be a subgroup of $g$. in this note we study the lattice $ll=lat(d,g)$ and the lattice $ll'$ of subgroups of $g$, normalized by $d$. we say that $ll$ satisfies sandwich classification theo...

Weconsider the sandwich problem, a generalization of the recognition problem introduced by Golumbic et al. (1995) [15], with respect to classes of graphs defined by excluding induced subgraphs. We prove that the sandwich problem corresponding to excluding a chordless cycle of fixed length k is NP-complete. We prove that the sandwich problem corresponding to excluding Kr \ e for fixed r is polyn...

MOTIVATION Giving a meaningful representation of a pedigree is not obvious when it includes consanguinity loops, individuals with multiple mates or several related families. RESULTS We show that finding a perfectly meaningful representation of a pedigree is equivalent to the interval graph sandwich problem and we propose an algorithm for drawing pedigrees.

light weight wood base sandwich panels have some special properties and their most important properties is high mechanical strength with its light weight. these panels can replace instead of traditional structural systems in iran. the purpose of this paper is investigating the mechanical properties of light weight wood base sandwich panels that have made from sunflower stalk wastes and particle...

X iv :1 70 4. 01 92 2v 1 [ m at h. C O ] 6 A pr 2 01 7 Sandwiches Missing Two Ingredients of Order Four José D. Alvarado Simone Dantas Dieter Rautenbach 1 Instituto de Matemática e Estat́ıstica, Universidade Federal Fluminense, Niterói, Brazil [email protected], [email protected] 2 Institute of Optimization and Operations Research, Ulm University, Ulm, Germany dieter.rautenbach@uni-ul...

In a recent paper, we introduced the simultaneous representation problem (defined for any graph class C) and studied the problem for chordal, comparability and permutation graphs. For interval graphs, the problem is defined as follows. Two interval graphs G1 and G2, sharing some vertices I (and the corresponding induced edges), are said to be “simultaneous interval graphs” if there exist interv...

Obstacle representations of graphs have been investigated quite intensely over the last few years. We focus on graphs that can be represented by a single obstacle. Given a (topologically open) polygon C and a finite set P of points in general position in the complement of C, the visibility graph GC(P ) has a vertex for each point in P and an edge pq for any two points p and q in P that can see ...

In the present paper, we derive some subordination and superordination results associated with a linear operator. Several sandwich-type results involving this operator are also proved. 2000 Mathematics Subject Classification: 30C45.

INTRODUCTION Lumbar hernia account for less than 2% of al abdominal hernias, been the Grynfelt-Lesshaft's hernia (GLH) more frequent than the others. With approximately 300 cases published in the literature, the general surgeon may have the chance of treat it ones in their professional life. CASE REPORT A 42-years old male with human immunodeficiency virus and Diabetes Mellitus presented to t...

In the present paper, we derive some subordination and superordination results associated with a linear operator. Several sandwich-type results involving this operator are also proved. 2000 Mathematics Subject Classification: 30C45.