Gerhard Ringel

Gerhard Ringel, a former UC Santa Cruz professor of mathematics, died on June 24 in his home. He was 88.Ringel was one of the world's foremost experts on combinatorics and graph theory. He is credited, along with J.W.T. Youngs, with solving the famous Heawood Conjecture. The conjecture gave the formula for the minimum number of colors necessary to color all graphs drawn on an orientable surface. minimum number of colors H(p) needed to color a map on a surface of genus p, namely
H(p) = [ 1/2( 7 + √( 48p + 1)) ].he had a love for butterflies and a massive 5,000 specimen collection.Ringel donated his world-class collection to the museum in 2006.Ringle came to Santa Cruz in 1967 to work at UCSC as a visiting professor. He returned in 1970, accepting an appointment as professor of mathematics. He spent the next 20 years teaching, achieving emeritus status in 1990.