Postal Meter Strip Honoring the Solution of the Four Color Problem
date: label: Date made
content: September 30, 1976
name: label: maker
content: Haken, Wolfgang
label: maker
content: University of Illinois
notes: label: Description
content: Wolfgang Haken and Kenneth Appel’s proof of the four color problem was one of the first theorems published that required computers in its confirmation. The Englishman Francis Guthrie had conjectured in 1852 that four colors suffice to color any map drawn on a sheet of paper in such a way that countries sharing a common border are different colors. Heinrich Heesch showed in 1969 that the conjecture could be solved by considering a set of some 8,900 configurations with boundaries of up to eighteen edges. Haken and Appel, working with computer scientist John Koch, reduced the number of configurations examined to 1,936. For each case, their program that four colors sufficed to color it. When Appel and Haken announced their result, their employer, the University of Illinois mathematics department, altered its postal meter to print "Four Colors Suffice." This is such a postal meter stamp.
label: Description
content: For a related computer printout, see 1999.0339.01.
label: Location
content: Currently not on view
place: label: place made
content: United States: Illinois, Urbana
topic: label: Subject
content: Mathematics
setName: label: See more items in
content: Medicine and Science: Mathematics
creditLine: label: Credit Line
content: Gift of Prof. Wolfgang Haken
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: 1999.0339.02
label: accession number
content: 1999.0339
label: catalog number
content: 1999.0339.02
objectType: label: Object Name
content: Postal Meter Strip
physicalDescription: label: Physical Description
content: paper (overall material)
label: Measurements
content: overall: .1 cm x 12.4 cm x 3.5 cm; 1/32 in x 4 7/8 in x 1 3/8 in