WWikiDDefinitionsVon Neumann successor
Definition·D006
The successor of x is x union {x}.
In words
The successor of x is x itself together with the singleton containing x.
Rests onno axioms yet
Never needed: F02 · F03 · F04 · F05 · F06 · F08 · F09 · F10 · F11 · F12 · F13 · F14 · A01 · A02 · A03 · A04 · A05 · A06 · A07 · A08 · A09 (computed from the citation graph, not asserted).
Remarks
Von Neumann successor. Together with D002 it builds the finite ordinals
,
,
, and so on, which are gathered into the set of natural numbers, and underlies the infinity axiom A05.
Used by
Propose an edit3 published revisions
- 7/11/2026 · Benjamin· Fix Mathlib link: add the #doc fragment doc-gen4's find endpoint requires (old link 404'd). Content unchanged.→what changed →
- 7/11/2026 · Benjamin· Backfill: add plain-English prose and Mathlib docs link→what changed →
- 7/11/2026 · Benjamin· Initial foundations seed→what changed →