Jerzy Łoś
Jerzy Łoś (; born 22 March 1920 in Lwów,
Poland (now
Lviv,
Ukraine) – 1 June 1998 in
Warsaw) was a Polish
mathematician,
logician,
economist, and
philosopher. He is especially known for his work in
model theory, in particular for "
Łoś's theorem", which states that any
first-order formula is true in an ultraproduct if and only if it is true in "most" factors (see
ultraproduct for details). In model theory he also proved many preservation theorems, but he gave significant contributions, as well, to
foundations of mathematics,
Abelian group theory and
universal algebra. In the 60's he turned his attention to
mathematical economics, focusing mainly on production processes and dynamic decision processes.
He was faculty at academies in
Wrocław,
Toruń, and
Warsaw.
In 1996, Łoś suffered from a severe brain stroke. He was thenceforward ill until his death in 1998.
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