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Card 109 of 9902026-09-17 issue

Observed arrival · 2026-09-17

Graceful Tree Search: Can Every Tree Be Labelled?

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Editorial interest 88/100 Selection signal · not a rating of the site

A distributed-computing project investigates a mathematical conjecture that every tree can receive a graceful labelling.

Landing page captured for the 2026-09-17 issue.

Field notes

Graceful Tree Search divides an exhaustive finite search into blocks that can run on volunteered computers. The page describes a 36-dot search containing 524,288 blocks and reports 765 validated blocks with 129 still in flight. Its mathematical test assigns the numbers 0 through n−1 to a tree’s dots and checks whether the resulting line differences use every value from 1 through n−1 exactly once. Earlier searches are reported to cover all trees up to 35 dots.

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Editorial observations of this landing page, not a rating.

○OpenPublic substance visible
⊠LoginAccess appeared gated
✦PrettyNotable craft visible
●ProPolished or operationally mature
◎NicheUnusually specific use
◉HumanPersonal, local, civic, or handmade

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Landing page observed 2026-09-17. The live site may have changed.