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Norman Woodason Johnson was a mathematician at Wheaton College, Norton, Massachusetts.
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In mathematics, Danzer's configuration is a self-dual configuration of 35 lines and 35 points, having 4 points on each line and 4 lines through each point. It is named after the German geometer Ludwig Danzer and was popularised by Branko Grünbaum. The Levi graph of the configuration is the Kronecker cover of the odd graph O4, and is isomorphic to the middle layer graph of the seven-dimensional hypercube graph Q7. The middle layer graph of an odd-dimensional hypercube graph Q2n+1(n,n+1) is a subgraph whose vertex set consists of all binary strings of length 2n + 1 that have exactly n or n + 1 entries equal to 1, with an edge between any two vertices for which the corresponding binary strings differ in exactly one bit. Every middle layer graph is Hamiltonian.
Roberts's triangle theorem, a result in discrete geometry, states that every simple arrangement of lines has at least triangular faces. Thus, three lines form a triangle, four lines form at least two triangles, five lines form at least three triangles, etc. It is named after Samuel Roberts, a British mathematician who published it in 1889.
References
- ↑ Interim Dean, College of Natural Science & Mathematics – Leah Berman, University of Alaska Fairbanks, July 17, 2018, retrieved 2019-08-17
- ↑ Grünbaum, Branko (2009), Configurations of points and lines, Graduate Studies in Mathematics, vol. 103, American Mathematical Society, Providence, RI, pp. 351–352, doi:10.1090/gsm/103, ISBN 978-0-8218-4308-6, MR 2510707
- ↑ "Two mathematics professors team up", Positively Charged: News from the College of Natural Science & Mathematics, University of Alaska Fairbanks, p. 5, July 17, 2018, retrieved 2019-08-19
- 1 2 3 4 Associate Partners: Leah Wrenn Berman, GReGAS, EuroGIGA Collaborative Research Project, retrieved 2019-08-17
- ↑ Harry J. Berman, Ph.D., Interim Chancellor (PDF), University of Illinois at Springfield , retrieved 2019-08-19
- ↑ Banas, Casey (May 10, 1993), "Quincy High School Wins Scholastic Bowl", Chicago Tribune
- ↑ Pamplin Society of Fellows, Lewis & Clark College, retrieved 2019-08-19
- ↑ Leah Berman at the Mathematics Genealogy Project
- ↑ Williams, Gordon (2018), "Branko Grünbaum, Geometer", Ars Mathematica Contemporanea, 15 (1)
- ↑ McGroarty, Erin (October 2, 2018), "Three women fill open seats on Fairbanks North Star Borough Assembly", Fairbanks Daily News-Miner
- ↑ "Assembly votes for gender-neutral pronouns in ordinance code", Toronto Star, Associated Press, March 2, 2019
