Mitchell rank for supercompactness

Erin Carmody

Mitchell rank for supercompactness

Erin Carmody

Abstract

This paper defines a Mitchell rank for supercompact cardinals. If $κ$ is a $θ$-supercompact cardinal then $o_{θ-sc}(κ) = \sup \{ o_{θ-sc}(μ) + 1 \ | \ μ\in m(κ)\}$, where $m(κ)$ is the collection of normal fine measures on $P_κθ$. We show how to force to kill the degree of a measurable cardinal $κ$ to any specified degree which is less than or equal to the degree of $κ$ in the ground model. We will also show how to softly kill the Mitchell rank for supercompactness of any supercompact cardinal so that in the forcing extension it is any desired degree less than or equal to its degree in the ground model, along with some results concerning strongly compact cardinals.

Mitchell rank for supercompactness

Abstract

This paper defines a Mitchell rank for supercompact cardinals. If

is a

-supercompact cardinal then

, where

is the collection of normal fine measures on

. We show how to force to kill the degree of a measurable cardinal

to any specified degree which is less than or equal to the degree of

in the ground model. We will also show how to softly kill the Mitchell rank for supercompactness of any supercompact cardinal so that in the forcing extension it is any desired degree less than or equal to its degree in the ground model, along with some results concerning strongly compact cardinals.

Paper Structure (25 theorems, 2 equations)

This paper contains 25 theorems, 2 equations.

Key Result

Theorem 1

If $\kappa$ is weakly measurable, then the measurability of $\kappa$ can be destroyed while preserving that $\kappa$ is weakly measurable.

Theorems & Definitions (42)

Theorem 1: Schanker
Theorem 2: Gitman
Theorem 3: Gitman
Theorem 4: Hamkins/Shelah
Theorem 5: Magidor
Theorem 6
proof
Lemma 7
proof
Lemma 8
...and 32 more