Published online by Cambridge University Press: 11 January 2022
Let
$\kappa $
be a regular uncountable cardinal, and
a cardinal greater than or equal to
$\kappa $
. Revisiting a celebrated result of Shelah, we show that if
is close to
$\kappa $
and
(= the least size of a cofinal subset of
) is greater than
, then
can be represented (in the sense of pcf theory) as a pseudopower. This can be used to obtain optimal results concerning the splitting problem. For example we show that if
and
, then no
$\kappa $
-complete ideal on
is weakly
-saturated.