Abstract

If F is a normal filter on a regular uncountable cardinal κ, let |f| be the F-norm of an ordinal function f. We introduce the class of positive ordinal operations and prove that if F is a positive operation then |F(f)| ≥ F(|f|). For each $\eta let f η be the canonical ηth function. We show that if F is a Σ operation then F(f η ) = f F(η) . As an application we show that if κ is greatly Mahlo then there are normal filters on κ of order greater than κ +