Pith. sign in

REVIEW 1 cited by

Constructing 5-chromatic unit distance graphs embedded in the Euclidean plane and two-dimensional spheres

Not yet reviewed by Pith; the record is open.

This paper has not been read by Pith yet. Machine review is queued; the pith claim, tier, and objections will appear here once it completes.

SPECIMEN: schema-true, not a live event

T0 review · schema-true

One-sentence machine reading of the paper's core claim.

pith:XXXXXXXX · record.json · timestamp

arxiv 2106.11824 v4 pith:CRURHDCQ submitted 2021-06-07 math.CO math.MG

classification math.COmath.MG
keywords chromaticembeddedgraphsunitdistanceplanespherevertices
verification ladder T0 review T1 audit T2 compute T3 formal

Signed reviews

No signed human review yet.

0 comments
read the original abstract

This paper is devoted to the development of algorithms for finding unit distance graphs with chromatic number greater than 4, embedded in a two-dimensional sphere or plane. Such graphs provide a lower bound for the Nelson-Hadwiger problem on the chromatic number of the plane and its generalizations to the case of the sphere. A series of 5-chromatic unit distance graphs on 64513 vertices embedded into the plane is constructed. Unlike previously known examples, these graphs do not contain the Moser spindle as a subgraph. The construction of 5-chromatic graphs embedded in a sphere at two values of the radius is given. Namely, the 5-chromatic unit distance graph on 372 vertices embedded into the circumsphere of an icosahedron with a unit edge length, and the 5-chromatic graph on 972 vertices embedded into the circumsphere of a great icosahedron are constructed.

Discussion (0). Continue with ORCID to comment.

Forward citations

Cited by 1 Pith paper

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score. Full citation record

  1. A Moser-spindle-free 5-chromatic unit distance graph on 2131 vertices in the plane

    math.CO 2026-08 conditional novelty 6.0 of 10

    A new 2131-vertex unit distance graph requiring 5 colors and containing no Moser spindle is constructed from the arcs of a 7-fold symmetric 21-vertex graph.

Pith tools