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Single Idea 13036

[filed under theme 4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / j. Axiom of Choice IX ]

Full Idea

Axiom of Choice: ∀A ∃R (R well-orders A). That is, for every set, there must exist another set which imposes a well-ordering on it. There are many equivalent versions. It is not needed in elementary parts of set theory.

Gist of Idea

Choice: ∀A ∃R (R well-orders A)

Source

Kenneth Kunen (Set Theory [1980], §1.6)

Book Ref

Kunen,Kenneth: 'Set Theory: Introduction to Independence Proofs' [North-Holland 1980], p.15


The 11 ideas from 'Set Theory'

Power Set: ∀x ∃y ∀z(z ⊂ x → z ∈ y) [Kunen]
Extensionality: ∀x ∀y (∀z (z ∈ x ↔ z ∈ y) → x = y) [Kunen]
Set Existence: ∃x (x = x) [Kunen]
Comprehension: ∃y ∀x (x ∈ y ↔ x ∈ z ∧ φ) [Kunen]
Replacement: ∀x∈A ∃!y φ(x,y) → ∃Y ∀X∈A ∃y∈Y φ(x,y) [Kunen]
Pairing: ∀x ∀y ∃z (x ∈ z ∧ y ∈ z) [Kunen]
Union: ∀F ∃A ∀Y ∀x (x ∈ Y ∧ Y ∈ F → x ∈ A) [Kunen]
Choice: ∀A ∃R (R well-orders A) [Kunen]
Infinity: ∃x (0 ∈ x ∧ ∀y ∈ x (S(y) ∈ x) [Kunen]
Foundation:∀x(∃y(y∈x) → ∃y(y∈x ∧ ¬∃z(z∈x ∧ z∈y))) [Kunen]
Constructibility: V = L (all sets are constructible) [Kunen]