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John W. Kennedy, professor of mathematics at QueensCollege, CUNY, will present “Orbix, LightsOut, and Related Vertex Neighborhood Switching Phenomena” 11 a.m. Thursday, June 28 at Pardee Hall room 201.
The lecture and tea reception at 10:30 a.m. in Pardee Hall room 216 are sponsored by the mathematics department and open to the public.
Kennedy’s research has ranged through chemistry, physics, data analysis, mathematical linguistics, and medical equipment design, with a focus on graph theory and combinatorics.
His lecture will deal with “Orbix” and “LightsOut,” which are two examples of graph puzzles in which each vertex of a graph G is considered to be in one of two states (often called ON and OFF). Both puzzles consider a vertex neighborhood switch operation that is applied to some subset of the vertices so that all of the vertices in a neighborhood of v change their state. Given a graph in an initial state with some vertices ON, the usual objective in both of the puzzles is to determine a neighborhood switch function (if one exists) that will turn all of the vertices OFF.