© 2003 by London Mathematical Society
© The London Mathematical Society
Weak Reflection at the Successor of a Singular Cardinal
amonja
School of Mathematics, University of East Anglia Norwich NR4 7TJ, m.dzamonja{at}uea.ac.uk
Mathematics Department, Hebrew University of Jerusalem 91904 Givat Ram, Israel
Rutgers University New Brunswick, NJ 08854-8019, USA, shelah{at}sunset.huji.ac.il
Received 14 March 2000. Revision received 1 March 2002.
The notion of stationary reflection is one of the most important notions of combinatorial set theory. Weak reflection, which is, as its name suggests, a weak version of stationary reflection, is investigated. The main result is that modulo a large cardinal assumption close to 2-hugeness, there can be a regular cardinal
such that the first cardinal weakly reflecting at
is the successor of a singular cardinal. This answers a question of Cummings, D
amonja and Shelah.