Colin Day, born in Poughkeepsie, N.Y. to James H. Day and Susan Hammond, died of gastric cancer on February 16th, 2012, in San Jose, CA. Colin was a highly accomplished man, a math Ph.D., elite-level cyclist, professional ballet dancer and yoga instructor.

In his thesis, Colin Day extends Vassiliev’s construction of finite-type invariants from knots to links, and elucidates Vassiliev’s construction in the process. Vassiliev’s construction never really got enough attention, Colin’s thesis is surely the best entry-point to it, and deserves to be widely read.

Colin taught high school math for fifteen years, most recently at the Cate School in Carpinteria, CA. He left his wife, Helen Moore; siblings, Kevin and Regan; step siblings. Betsey, Bobby and Beth; nieces, Lilly and Olivia; nephews, Gabriel, Sam, Nathaniel, William, Robert and Thomas; stepfather, Bob; great-aunt, Stella; and uncle, Roger. Funeral was held on February 23rd in San Jose, CA. A memorial was held in Carpinteria, CA, on March 31st.