Stanisław Świerczkowski

Stanisław Świerczkowski, known as Stash (16 July 1932 to 30 September 2015), was a Polish mathematician famous for his solutions to two iconic problems posed by Hugo Steinhaus, the three-gap theorem and the non-tetratorus theorem. He was born in Toruń, Poland; his father was captured in Soviet-controlled Poland and murdered in the 1940 Katyń Massacre, and he belonged to the Polish nobility through his father. The three-gap theorem belongs to the field of Diophantine approximation, and the non-tetratorus theorem, published in 1958, states that it is impossible to construct a closed chain of regular tetrahedra placed face to face. In 1964, in joint work with Jan Mycielski, he established an early result on the axiom of determinacy, that it implies all sets of real numbers are Lebesgue measurable. His last work gave proofs of Gödel's incompleteness theorems using hereditarily finite sets.