Kaplansky sings Kaplansky (and Pi)

     I first knew of mathematician Irving Kaplansky (1917-2006) through his monograph, Infinite Abelian Groups -- it was one of my texts for a graduate seminar (with Gene Levy) at the University of Oklahoma in the 1960s.  Later I knew Kaplansky as a songwriter, author of new lyrics for "That's Entertainment."  Kaplansky's adaptation, "That's Mathematics," dedicated to his former student, math-musician-songwriter Tom Lehrer, and to his daughter, singer Lucy Kaplansky, is given below.
      In 1999, in Science News, writer Ivars Peterson (now Director of Publications for the MAA -- Mathematical Association of America) wrote an article about Kaplansky's songwriting in which he mentions  his daughter, Lucy Kaplansky, a singer who frequently performs her father's songs.  A YouTube recording of Lucy singing "The Song of Pi" (in which there is a correspondence between musical notes and the first fourteen digits of pi) is available here.  (Lyrics for "The Song of  Pi" and information about the correspondence are available in Peterson's article.)

Four -- square, colors, theorem, poem

During my doctoral study days at the University of Oklahoma I knew several mathematicians who were working on graph theory problems -- and a couple of them worked on problems related to the Four Color Conjecture -- a conjecture (dating back to around 1850) that became a theorem in 1976 with a proof by Kenneth Appel and Wolfgang Haken verifying (using many hours of computer time).  It asserts that four colors are sufficient to color any plane map so that no pair of adjacent regions have the same color.  This theorem has been again on my mind since reading the obituary of Kenneth Appel, who died on April 19.
Here is a link to an earlier posting (5 November 2011) on the Four Color Problem with a poem by Frank Bernhart.  And here, repeated from that post, is my poetic version of the Four Color Theorem:

        F O U R
        F O U R
        F O U R
        F O U R