# Definition:Basic Universe Axioms

## Definition

Let $V$ be a basic universe.

Then $V$ is to satisfy the following axioms:

### $\text A 1$: Axiom of Transitivity

$V$ is a transitive class.

### $\text A 2$: Axiom of Swelledness

$V$ is a swelled class.

### $\text A 3$: Axiom of the Empty Set

The empty class $\O$ is a set, that is:

$\O \in V$

### $\text A 4$: Axiom of Pairing

Let $a$ and $b$ be sets.

Then the class $\set {a, b}$ is likewise a set.

### $\text A 5$: Axiom of Unions

Let $x$ be a set (of sets).

Then its union $\bigcup x$ is also a set.

### $\text A 6$: Axiom of Powers

Let $x$ be a set.

Then its power set $\powerset x$ is also a set.