Blanche Descartes
Blanche Descartes is the pseudonym of a group of English mathematician William Thomas Tutte, R. Leonard Brooks (1916-1993), Arthur Harold Stone (1916-2000) and the statistician Cedric Smith ( 1917-2002 ). The name Blanche contains the initials of the first names of the four (Bill, Leonard, Arthur, Cedric ), the name can be understood as a pun to carte blanche or Descartes.
The four mathematicians in the mid- 1930s, met as students at Trinity College, Cambridge, where they founded the Trinity Mathematical Society. All four are available as authors of a joint work on the division of a square into smaller squares known (though they no pseudonym used ) .. Under Blanche Descartes published a decomposition of a square into rectangles of equal area ( decomposition of Blanche ).
She published under the pseudonym of approximately 30 works, including for recreational mathematics, combinatorics, but also humorous poems, and similar mathematical jokes. For example, they published a solution to the problem of counterfeit coins: Given 12 pennies ( give a shilling ), one of them is wrong ( and weighs a little more), what is the minimum number of weighings with a balance scale are needed to discover the false coin? The answer is three, Blanche Descartes found a solution in the general case for n coins.
Tutte published under Blanche Descartes various work on graph theory, for example for coloring of graphs. So he published an example of snarks (the name comes from Martin Gardner by Lewis Carroll, Hunting of the Snark ), ie, a graph in which each node has three neighbors and whose edges can not be colored with three colors, without at one of the two edge nodes are the same color. They are known to the four color problem is with the statement by Tait equivalently, that there are no planar snarks since the studies of Peter Guthrie Tait. The first Snark discovered comes from Julius Peter Christian Petersen (1898), two more of Danilo Blanuša (1946 ), Blanche Descartes discovered the fourth, George Szekeres 1973 the fifth and Rufus Isaacs took place in 1975 two infinite families.