Set Theory Axioms (SE212)

Types as Sets

Axiom - Types as Sets

Set Comprehension

Set Builder Notation Formally

Axiom - Set Comprehension
Axiom - Set Comprehension

Constants: Empty Set and Universal Set

Axiom - Empty Set
Axiom - Universal Set

Predicate: Set Equality

Axiom - Set Equality

Predicate: Subset

Formally

Axiom - Subset

Axiom - Proper Subset


(see Set Equality)

Function: Set Size

Definition

The cardinality of a set is the number of elements in a finite set, denoted with magnitude or absolute value bars, denoted as or

Function: Power Set

$

powerset

Axiom - Power Set
Remark

If is a finite set with cardinality , then . This is why the power set is sometimes denoted as .

Functions: Union and Intersection

Axiom - Set Union
Axiom - Set Intersection

Functions: Difference and Complement

Axiom - Set Difference

Axiom - Absolute Complement

Relations

Cartesian Product

Axiom - Cartesian Product

Domain, Range

Axiom - Domain

For the relation

Axiom - Range

For the relation

Properties

For two relations and :

Domain properties:

Range properties (nearly identical):

Inverse Relation

Axiom - Inverse

Properties

Pretty self evident

Identity Relation

Axiom - Identity

Relational Composition

Axiom - Relational Composition

Properties

For , , :

  1. Assosiative:
  2. Inverse distributive:
  3. Domain identity:
  4. Range identity:
  5. Identity: ,

Relational Image

Axiom - Relational Image

Properties

Restrictions and Subtractions

Axiom - Domain Restriction

Axiom - Range Restriction

Axiom - Domain Subtraction

Axiom - Range Subtraction

Properties

For and :

Relational Overriding

Axiom - Relational Overriding

For , :

Properties

For :

  1. Idempotent:
  2. Associative: