IPM
30
YEARS OLD

## “School of Mathematics”

Back to Papers Home
Back to Papers of School of Mathematics

Paper   IPM / M / 16022
 School of Mathematics Title: Tanaka's theorem revisited Author(s): Saeideh Bahrami Status: To Appear Journal: Arch. Math. Logic Supported by: IPM
Abstract:
Tanaka (1997) proved a powerful generalization of Friedmanâs selfembedding theorem that states that given a countable nonstandard model (M;A) of the subsystem WKL0 of second order arithmetic, and any element m of M, there is a self-embedding j of (M;A) onto a proper initial segment of itself such that j fixes every predecessor of m.