Peter Aczel has written:

'Non-Well-Founded Sets (Csli Lecture Notes, No 14)'

'Non-well-founded sets' -- subject(s): Axiomatic set theory

Set theory was founded by Georg Cantor in 1873.

Novanet: THEORY

The positivist theory of criminology was founded by Cesare Lombroso, an Italian criminologist, in the late 19th century. Lombroso believed that criminals were biologically different from non-criminals, and he introduced the concept of the "born criminal."

A theory is a scientific principle, a suggested explanation for a natural phenomena that is supported by well founded evidence and/or repeatable experimental results.
A Theory is a set of ideas or explanations on a particular phenomenon gained through scientific study