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Single Idea 18465

[filed under theme 8. Modes of Existence / A. Relations / 4. Formal Relations / b. Equivalence relation ]

Full Idea

R is an equivalence relation on A iff R is reflexive, symmetric and transitive on A.

Gist of Idea

An 'equivalence' relation is one which is reflexive, symmetric and transitive

Source

Kenneth Kunen (The Foundations of Mathematics (2nd ed) [2012], I.7.1)

Book Ref

Kunen,Kenneth: 'The Foundations of Mathematics' [College Publications 2012], p.24


The 12 ideas from Kenneth Kunen

An 'equivalence' relation is one which is reflexive, symmetric and transitive [Kunen]
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]