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Conjecture

Ringel-Kotzig Conjecture

Combinatorics

The Ringel-Kotzig conjecture, also known as the graceful tree conjecture, is a major open problem in graph theory named after Gerhard Ringel and Anton Kotzig. A graceful labeling of a graph with m edges labels its vertices with distinct integers from 0 to m so that each edge is uniquely identified by the absolute difference between its two endpoint labels; a graph admitting such a labeling is called graceful. The conjecture hypothesizes that every tree is graceful, and it remains open. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/

Facts
Statement
Every tree is graceful. 1
Progress Toward Resolution
Still open. The weaker Ringel conjecture was partially proven in 2020 by Montgomery, Pokrovskiy and Sudakov, and all trees up to 35 vertices are verified graceful. 1
Classification
Resolution Status
Open 1
Prize Status
Prize Status (category)
No Prize Offered 1
Connections

In Branch

Source Graceful Labeling (Wikipedia)
Sources
1. Graceful Labeling (Wikipedia)
  • Ringel-Kotzig conjecture paragraph
    It hypothesizes that all trees are graceful.
  • Status paragraph
    It is still an open conjecture, although a related but weaker conjecture known as 'Ringel's conjecture' was partially proven in 2020 by Montgomery, Pokrovskiy and Sudakov.
  • Lead section
  • In Branch: Graph Theory, Lead sentence
    In graph theory, a graceful labeling of a graph with m edges is a labeling of its vertices with some subset of the integers from 0
View the Source
Ringel-Kotzig Conjecture (Wikipedia)
Wikimedia FoundationLead section
Quote, Lead section
It hypothesizes that all trees are graceful.
View the Source
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