Find a proof that provides a solution to the famous problem about covering a map with four colors, which dates back to Francis Guthrie in 1852.

Find an overview of Francis Guthrie's Four Colour Conjecture. Includes reference articles and related links.

Examine theories, postings, and brain teasers regarding this elusive aspect of the universe. Includes chat, articles, and reports.

Learn about manifolds, sphere packings, and hyperbolic triangles. Includes details about knots and hypercubes.

View a tessellation of the hyperbolic plane by triangles. Includes an explanation of the software, Cabri.

Explore the hypercube and hyper-torus in the fourth dimension. Includes animations and references.

Furnishes a list of resources about non-Euclidean geometry. Includes details about the parallel postulate and topology.

Features a history of non-Euclidean geometry. Includes details about the mathematicians Bolyai, Lobachevsky and Riemann.

Features details about how to explore non-Euclidean geometry with the LOGO computer language. Includes a compete list of references.

Features software that simulates hyperbolic straightedge and compass constructions. Provides basic information about non-Euclidean geometry.

Learn about curved space and non-Euclidean geometry. Includes details about Einstein's Theory of Relativity.