Jerzy Łoś

Jerzy Łoś (born March 22, 1920 in Lwów, Poland (now Lviv, Ukraine) – June 1, 1998 in Warsaw) ([ˈjɛʐɨ ˈwɔɕ]) 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.

Selected publications

• Łoś, Jerzy (1955) Quelques remarques, théorèmes et problèmes sur les classes définissables d'algèbres. Mathematical interpretation of formal systems, pp. 98--113. North-Holland Publishing Co., Amsterdam.