Does anyone know what this is and why it is connected to 4ct?

• http://plants.jstor.org/compilation/erica.guthriei

My links:

• GitHub (the current repo for the software)
• Sourceforge (the old repository for the software)
• Prezi (A very short presentation)
• YouTube (Some videos of the Java and Python applications)

General info and history of the theorem:

• Wikipedia
• MacTudor
• MathWorld
• NRich (University of Cambridge)
• Citizendium
• Georgia Institute of Technology
• https://celebratio.org

Peoples who proved the theorem (according to Wikipedia):

• 1976: Kenneth Ira Appel + Wolfgang Haken based on the work of Kempe
• 1997: Robertson, Sanders, Seymour, and Thomas based on the work of Appel & Haken
• 2005: Georges Gonthier based on the work of Robertson, Sanders, Seymour, and Thomas

Books:

• What Is Mathematics? An Elementary Approach to Ideas and Methods
• Four Colors Suffice: How the Map Problem Was Solved
• The Four-Color Theorem: History, Topological Foundations, and Idea of Proof
• Graphs, Colourings and the Four-Colour Theorem

Other sites with applications to color maps or related apps:

• https://www.kleemans.ch/four-color-theorem-map-solver
• http://www.kongregate.com/games/Onefifth/flood-fill – NOT WORKING Aug/2022 (Based on flash)
• http://www.nikoli.com/en/take_a_break/four_color_problem – DEAD Aug/2022
• http://www.gamedesign.jp/flash/fourcolor/fourcolor.html – NOT WORKING Aug/2022 (Based on flash)
• http://bjarne.altervista.org/rct/introduction.html – DEAD Aug/2022
• http://www.iqflash.com/four-color.shtml – NOT WORKING Aug/2022 (Based on flash)
• http://www.kanadas.com/ccm/coloring/index.html – NOT WORKING Aug/2022 (Based on applets)

Other:

• Small Four-color-map Wooden Jigsaw Puzzle
• Flickr images for the 4ct
• Fantastic four
• Google coloring search

YouTube:

• https://www.youtube.com/watch?v=mXcMkoo0pas (Georges Gonthier)
• https://www.youtube.com/watch?v=jUNUGxNdodU (David Glance)
• https://www.youtube.com/watch?v=adZZv4eEPs8 (Math at Andrews)
• https://www.youtube.com/watch?v=NgbK43jB4rQ& (Numberphile)
• http://www.youtube.com/watch?v=0gt503wK7AI (Using a SAT solver to color a map)
• http://www.youtube.com/watch?v=bRjqHtLIZ8U (Four-Color Maps)

Discussions:

• http://rjlipton.wordpress.com/2009/04/24/the-four-color-theorem
• http://mathoverflow.net/questions/44673/human-checkable-proof-of-the-four-color-theorem
• http://divisbyzero.com/2008/12/09/four-color-theorem-applets – NOT WORKING Aug/2022 (Based on applets)