Mathematical proof is unfortunately an obstacle for many undergraduate mathematics majors. Based on his work with undergraduates, Harel has hypothesized different "proof schemes"--ways by which students convince themselves, and convince others, that particular results are true. These proof schemes will be outlined and illustrated during the session. Implications for instruction will also be mentioned.

Guershon Harel, Purdue University, West Lafayette
Larry K. Sowder, San Diego State University