An illustration of the fact that in a game played over the unit square, if either player has a non-step-function optimal strategy, the opposing player has a unique optimal strategy. Examples are included which show that games with well behaved payoffs can have unique solutions which are more or less pathological.
Glicksberg, Irving Leonard and Oliver Alfred Gross, A Class of Games with Unique Solutions. Santa Monica, CA: RAND Corporation, 1951. https://www.rand.org/pubs/research_memoranda/RM538.html. Also available in print form.
Glicksberg, Irving Leonard and Oliver Alfred Gross, A Class of Games with Unique Solutions, Santa Monica, Calif.: RAND Corporation, RM-538-PR, 1951. As of June 16, 2021: https://www.rand.org/pubs/research_memoranda/RM538.html