We prove the consistency of a singular cardinal λ with small value of the ultrafilter number u λ, and arbitrarily large value of 2 λ.
Bibliographical noteFunding Information:
∗Corresponding author. †Research supported by the United States-Israel Binational Science Foundation, and ISF grant no. 242/03. This is publication 1002 of the second author. Key words and phrases: ultrafilter number, pcf theory, large cardinal. Mathematics Subject Classification: 03E05, 03E55.
- large cardinal
- pcf theory
- ultrafilter number