Alice: "I am insane." Bob: "I am pure." Charlie: "I am applied." Dorothy: "I am sane." Alice: "Charlie is pure." Bob: "Dorothy is insane." Charlie: "Bob is applied." Dorothy: "Charlie is sane."Describe the four mathematicians, given that:

- pure mathematicians tell the truth about their beliefs
- applied mathematicians lie about their beliefs
- sane mathematicians' beliefs are correct
- insane mathematicians' beliefs are incorrect
Source:© Copyright 2000 Stan Wagon. Reproduced with permission.Mathematics and Informatics Quarterly9:4 Dec 1999 p. 162

22 February 2000