During the fall of 1990, David Seetapun was said to have "used a very interesting 0′′′- priority argument to prove that every r.e.
[1] Seetapun received a PhD in logic from Cambridge in 1991, the topic was "Contributions to recursion theory".
[2][3][4] He also proposed the so called "Seetapun Enigma", a mathematical puzzle that was not solved until 2010 by Chinese undergraduate student Liu Lu.
Seetapun made a reputation for himself managing a trading venture with mathematical models, and has been cited as "Goldman's top London proprietary options trader", making over $500m.
In 1998 his models started to fail causing a loss of his own funds as well as for the firm.