Category Archives: problems and puzzles

Four questions about fuzzy rankings

The National Research Council is getting ready to release a new assessment of graduate-education programs in the U.S. The previous study, published in 1995, gave each Ph.D.-granting department a numerical score between 0 and 5, then listed all the programs … Continue reading

Posted in computing, games, mathematics, problems and puzzles, statistics | 22 Comments

A twist of fate

The school of philosophy called Antipodianism briefly flourished on the fringes of the Hellenistic world more than 2,000 years ago. The sect held that every person has an opposite number, a mirror image who inverts all our beliefs, feelings, actions … Continue reading

Posted in problems and puzzles | 6 Comments

A shy woodland creature

Martin Gardner died over the weekend. He was 95 and living in Norman, Oklahoma, not too far from his birthplace in Tulsa. Like many others, I grew up on Martin’s “Mathematical Games” column in Scientific American. Later I joined the … Continue reading

Posted in games, problems and puzzles | 5 Comments

Gruenberger’s prime path

Fred Gruenberger may well have been the first blogger on computational topics. When he was writing, back in the 1970s, there was no RSS, and so he distributed his musings in a monthly newsletter called Popular Computing. A typical issue … Continue reading

Posted in computing, mathematics, problems and puzzles | 8 Comments

The Chromatic Number of Liechtenstein

Four colors suffice for any planar map: We’ve known that since 1977. If a map is divided into countries or provinces or other regions, and you want to color the map so that no two adjacent regions have the same … Continue reading

Posted in mathematics, problems and puzzles | 5 Comments