It is proved that $\Pi^1_1$ -indescribability in $P_{\kappa}\lambda$ can be characterized by combinatorial properties without taking care of cofinality of $\lambda$ . We extend Carr's theorem proving that the hypothesis $\kappa$ is $2^{\lambda^{<\kappa}}$ -Shelah is rather stronger than $\kappa$ is $\lambda$ -supercompact.

We characterize some large cardinal properties, such as $\mu$-measurability and $P^2(\kappa)$-measurability, in terms of ultrafilters, and then explore the Rudin-Keisler (RK) relations between these ultrafilters and supercompact measures on $P_\kappa(2^\kappa)$. This leads to the characterization of $2^\kappa$-supercompactness in terms of a measure on measure sequences, and also to the study of a certain natural subset, $\mathrm{Full}_\kappa$, of $P_\kappa(2^\kappa)$, whose elements code measures on cardinals less than $\kappa$. The hypothesis that $\mathrm{Full}_\kappa$ is stationary (a weaker assumption than $2^\kappa$-supercompactness) is (...) equivalent to a higher order Lowenheim-Skolem property, and settles a question about directed versus chain-type unions on $P_\kappa\lambda$. (shrink)