David Singmaster

Career

David Singmaster was a student at the California Institute of Technology in the late 1950s. He intended to be a chemist, then changed to physics. He only became really interested in mathematics in his final year when he took some courses in algebra and number theory. In his last semester, his algebra teacher posed a question the teacher didn't know the answer to and Singmaster solved it, eventually leading to two papers. He gained his PhD at the University of California, Berkeley, in 1966.

Singmaster moved to London in 1970. The "Polytechnic of the South Bank" had been created from a merger of institutions in 1970, and Singmaster became a lecturer in the department of Mathematical Sciences.

Around 1972 he attended the Istituto di Matematica in Pisa for a year having won a research scholarship. He was promoted to a Readership (a Research Professorship) at the South Bank polytechnic in September 1984. The polytechnic became London South Bank University in 1992, and Singmaster was the professor of mathematics at the "School of Computing, Information Systems and Mathematics". He also became an honorary research fellow at University College London.

Rubik's Cubes

Singmaster's association with Rubik's Cubes dates from August 1978, when he saw a Cube (at that time a rarity) at the International Congress of Mathematicians in Helsinki. Some other mathematicians at the conference, including John Conway and Roger Penrose, already had one.

Singmaster quickly acquired a Cube (in exchange for a copy of an M. C. Escher book) and was able to solve it by early September 1978. He has said that it took him "two weeks, on and off" to find a general solution for the Cube. He devised his notation for recording moves (now known as the Singmaster notation) in December 1978. In June 1979 he wrote one of the first articles about the Cube in The Observer newspaper.

In October 1979 he self-published his Notes on the "Magic Cube". The booklet contained his mathematical analysis of Rubik's Cube, allowing a solution to be constructed using basic group theory. In August 1980 he published an expanded 5th edition of the book retitled as Notes on Rubik's "Magic Cube". It included the results of his correspondence with other "cubologists", and included details on monotwists, U-flips, Cayley graphs, and wreath products. The book contained his own "step by step solution" for the Cube, and it is accepted that he was a pioneer of the general Layer by Layer approach for solving the Cube. If you managed to solve the Cube using his method then Singmaster suggested that you should:

Scream HOORAY!! Buy a round of drinks. Send me a cheque. Tell the orderlies that they can let you out now. Etc. etc.

The book also contained a catalogue of pretty patterns including his "cube in a cube in a cube" pattern which he had discovered himself "and was very pleased with". In 1981, at the height of the Rubik's Cube craze, the book was republished by Penguin Books, with a US edition by Enslow Publishers. There were also Dutch and Spanish translations. He estimates that he sold around 50 to 60 000 copies of his book. Much of the mathematical content of the book was later reworked by Alexander H. Frey in collaboration with Singmaster to create their Handbook of Cubik Math published in 1982.

Singmaster has been described as "one of the most enthusiastic and prolific promoters of the Cube". In September 1981 he was said to be devoting "almost 100%" of his time to promoting, reporting, marketing and analysing the Cube. He soon began publishing a quarterly newsletter called the Cubic Circular which was published between 1981 and 1985.

Puzzles

Singmaster has one of the world's largest collections of books on recreational mathematics, which he reported in 1996 contained over 4700 works. He also collects books on cartoons, humour, and language. He has a huge collection of mechanical puzzles, which he stated in 2003 contained "perhaps 3000 puzzles, of which about 400 are Rubik Cubes and variants".

From around 1980 to 1982 he ran his own puzzle company, David Singmaster Ltd, which stocked "over 100 puzzles and books". However the venture lost him "a fair amount of money" and led to prolonged tax negotiations. He referred to this period of his life as "a massive overdose of cubism".

Singmaster is both a puzzle historian and a composer of puzzles, and he describes himself as a "metagrobologist". Many of his puzzles have appeared in publications such as BBC Focus, Games & Puzzles, the Los Angeles Times, and the Weekend Telegraph. He published a collection of his puzzles in his 2016 book Problems for Metagrobologists. From around 2006 Singmaster was a director at the New York-based Conjuring Arts Research Center, retiring from the position (becoming Director Emeritus) in 2013. He was instrumental in the re-discovery of one of the world's oldest books on puzzles and magic illusions when he came across a reference to the work in a 19th-century manuscript. The recovered text, De viribus quantitatis (English: On The Powers Of Numbers) was penned by Luca Pacioli, a Franciscan monk who lived around 1500.

Singmaster's conjecture

In combinatorial number theory, Singmaster's conjecture states that there is a finite upper bound on the number of times a number other than 1 can appear in Pascal's triangle. Paul Erdős suspected that the conjecture is true, but thought it would probably be very difficult to prove. The empirical evidence is consistent with the proposition that the smallest upper bound is 8.

Media appearances

In November 1981, he appeared on the scifi-themed BBC puzzle show The Adventure Game. From 1998 to 1999 he was a frequent panelist on the BBC Radio 4 show Puzzle Panel.

Personal life

Singmaster has been married twice, the second time to Deborah in 1972. They have one daughter, Jessica, adopted in 1976.

Books

Reference works

Newsletters

Articles