Doug Ensley
Prepared Talks:
- Invariants under Group Actions to Amaze Your Friends
- Some card tricks have a spectator shuffle a deck of cards in a specific way before the magician performs some feat which seems impossible for a fairly mixed deck of cards. The mathematical idea is that by understanding invariant properties of the group action (shuffling!) on the deck, the performer can find order where the spectators believe they have left disorder. We will use some specific tricks and a little discrete mathematics to illustrate the idea.
- Eeny-Meeny-Miney-Moe in Higher Mathematics
- The classical Josephus Problem entails n people (labeled 1,2,...,n, of course) standing in a circle and every kth person being eliminated (starting with person k) until only one person is left. The usual question is, “Who is the last person standing?”, which is of course related to the well-known eeny-meeny-miney-moe method of choosing sides on a playground. We will survey known answers to the Josephus Problem as well as present other questions and variations sure to spark new interest in this old problem from recreational mathematics.
Contact Information:
- Institution: Shippensburg University
- Phone Number: 717.477.1477
- e-Mail Address: deensley@ship.edu
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