Spies and Double Agents
Two logical spies, M and N, sent reports to Z, the head of the CIA. Z suspected one to be a double agent. The task is to find which spy is trustworthy and always tells the truth, which spy is untrustworthy and always lies, and to evaluate their statements, , , , …, for their truth values. The contents of the statements are classified. For negation, conjunction, disjunction, implication, and equivalence, they used the symbols , , , , . For readability, F (for False) is left blank in the truth tables.
The idea for the Demonstration comes from .
 D. Shasha, The Puzzling Adventures of Dr. Ecco, New York: W. H. Freeman, 1988 p. 41.
"Spies and Double Agents"
Wolfram Demonstrations Project
Published: February 26 2013