New York Combinatorics Seminar

Sponsored by the Graduate Center's Math Department and Computer Science Department

Fridays 11:45 am - 12:45 am in Room 4422

This seminar covers a wide range of topics in combinatorics and its applications.

The CUNY Graduate Center is located at 365 Fifth Avenue (at the corner of 34th Street), New York. It can be easily reached by subway using the B,D,F,N,Q,R, or 6 train.

Seminar Co-Organizers:
CUNY: Nadia Benakli (City Tech) Ezra Halleck (City Tech), Sandra Kingan (Brooklyn College), Joseph Malkevitch (York College), Kerry Ojakian (BCC), Mingxian Zhong (Lehman College),
Montclair State University: Deepak Bal, Jonathan Cutler
Hofstra University: Kira Adaricheva, Eric Rowland

Fall 2019 Talks

Please note the new room number: 4422

Sep 20, 2019: Kerry Ojakian (BMCC, CUNY)

Title: Bounding the k-rainbow total domination number
Abstract: A k-rainbow dominating function of a graph G is the following: a function f which assigns a subset of [k] = {1,2,, k} to each vertex of G, such that if a vertex v is assigned the empty set, then the values assigned to v's neighbors union to [k]. A k-rainbow *total* dominating function is a function f which satisfies the following additional condition: if a vertex is assigned a singleton set {i} then for some neighbor u, we have i in f(u). In either case, the weight of f is the sum of |f(v)| as v ranges over the vertices of G. For a graph G, the k-rainbow domination number is defined as the minimum weight k-rainbow dominating function for G, and the k-rainbow *total* domination number is defined as the minimum weight k-rainbow total dominating function for G. I will present bounds on the rainbow total domination number in terms of the usual domination number, the total domination number, the rainbow domination number and the rainbow total domination number. Along with a number of partial results, I will present questions and conjectures, including a Vizing-like conjecture about graph products for the rainbow total domination number.

Previous Co-Organizers

Christopher Hanusa (Spring 2011 - Spring 2015)

Previous Speakers

Spring 2019
Fall 2018
Spring and Summer 2018
Fall 2017
Spring 2017
Fall 2016
Spring 2016
Fall 2015
Spring 2015
Fall 2014
Spring 2014
Fall 2013
Spring 2013
Fall 2012
Spring 2012
Fall 2011
Spring 2011
Previous Talks hosted by Janos Pach