User:David Eppstein
About me[edit]
I'm a computer science professor at UC Irvine, in Orange County, California. See my home page or blog or even my Wikipedia article for more about me.
Much of my Wikipedia editing is on mathematics articles, but I've also edited articles on computer science, academic biography, the arts, and California geography, among many other topics. I've also contributed many diagrams and photographs to Wikipedia and Wikimedia Commons.
As an employee of a public university I believe that public outreach is part of my job description, and in that sense that my edits here to subjects within my professional expertise are paid edits. However, the topics and content of my editing here are wideranging and entirely selfdirected. I neither participate in, nor condone, paid edits for specific articles or specific content.

Wikibooks[edit]
Click on the titles, not on the cover images!





Did you know?[edit]
 ... that exercises in the fair division of food (example pictured) are often used to teach unit fractions? (23.04)
 ... that a simple polygon through all the points of a threebythree grid must pass straight through some of the points, rather than turning at each of them? (23.03)
 ... that French astrochemist Christine Joblin cocreated a webcomic to popularize her research on the origins of cosmic dust? (23.03)
 ... that after Archimedes first defined convex curves, mathematicians lost interest in their analysis until the 19th century, more than two millennia later? (23.01)
 ... that tensided gaming dice (examples pictured) have kiteshaped faces? (22.11)
 ... that Nicole LloydRonning returned to astrophysics research after a tenyear hiatus, aided by an American Physical Society award for women with interrupted careers? (22.11)
 ... that it took 90 years to replace the "unconvincing" original proof of Roberts's triangle theorem, on the number of triangles formed by systems of lines, with a correct proof? (22.11)
Good articles[edit]
 Alexandrov's uniqueness theorem – Polyhedra are determined by surface distance
 antiparallelogram – Polygon with four crossed edges of two lengths
 Mark Barr – EnglishAmerican inventor and polymath (1871–1950)
 Beckman–Quarles theorem – Unitdistancepreserving maps are isometries
 binary logarithm – Exponent of a power of two
 book embedding – Graph layout on multiple halfplanes
 Borromean rings – Three linked but pairwise separated rings
 bucket queue – Data structure for integer priorities
 Cairo pentagonal tiling – Tiling of the plane by pentagons
 clique problem – Task of computing complete subgraphs
 component (graph theory) – Maximal subgraph whose vertices can reach each other
 constructible number – Number constructible via compass and straightedge
 convex curve – Type of plane curve
 convex hull – Smallest convex set containing a given set
 copwin graph – Type of graph related to pursuit–evasion
 curve of constant width – Shape with width independent of orientation
 curveshortening flow – Motion of a curve based on its curvature
 De Bruijn–Erdős theorem (graph theory) – On coloring infinite graphs
 De quinque corporibus regularibus – 15th century book on polyhedra
 Dehn invariant – Value determined from a polyhedron
 directed acyclic graph – Directed graph with no directed cycles
 double bubble theorem – On smallest surface enclosing two volumes
 Doyle spiral – Circle packing arranged in spirals
 dual graph – Graph representing faces of another graph
 dyadic rational – Fraction with denominator a power of two
 Erdős–Ko–Rado theorem – Upper bound on intersecting set families
 Erdős–Straus conjecture – On unit fractions adding to 4/n
 Euclid–Euler theorem – Characterization of even perfect numbers
 Euclidean distance – Length of a line segment
 Euclidean minimum spanning tree – Shortest network connecting points
 factorial – Product of numbers from 1 to n
 farthestfirst traversal – Sequence of points far from previous points
 feedback arc set – Edges that hit all cycles in a graph
 Fermat's right triangle theorem – Rational right triangles cannot have square area
 Fibonacci nim – Game of taking coins from a pile
 free abelian group – Algebra of formal sums
 Garden of Eden (cellular automaton) – Pattern that has no predecessors
 Andrew M. Gleason – American mathematician and educator
 Ronald Graham – American mathematician (1935–2020)
 Halin graph – Mathematical tree with cycle through leaves
 handshaking lemma – Every graph has evenly many odd vertices
 harmonic series (mathematics) – Divergent sum of all positive unit fractions
 Heilbronn triangle problem – On point sets with no smallarea triangles
 C. Doris Hellman – American historian of science
 ideal polyhedron – Shape in hyperbolic geometry
 infinity symbol – Mathematical symbol, "∞"
 integer sorting – Computational task of sorting whole numbers
 isosceles triangle – Triangle with at least two sides congruent
 Vojtěch Jarník – Czech mathematician
 Jessen's icosahedron – Rightangled nonconvex polyhedron
 Kawasaki's theorem – Description of flat onevertex origami
 Keller's conjecture – Geometry problem on tiling by hypercubes
 Kepler triangle – Right triangle related to the golden ratio
 kite (geometry) – Quadrilateral symmetric across a diagonal
 Harry R. Lewis – American computer scientist
 Laves graph – Periodic spatial graph
 linear probing – Computer programming method for hashing
 logic of graphs – Logical formulation of graph properties
 Malfatti circles – Three tangent circles in a triangle
 midsphere – Sphere tangent to every edge of a polyhedron
 Möbius strip – Nonorientable surface with one edge
 mutilated chessboard problem – On domino tiling after removing two corners
 nearestneighbor chain algorithm – Stackbased method for clustering
 nothreeinline problem – Geometry problem on grid points
 opaque set – Shape that blocks all lines of sight
 Pick's theorem – Formula for area of a grid polygon
 polygonalization – Polygon through a set of points
 prime number – Evenly divided only by 1 or itself
 Prince Rupert's cube – Cube that fits through hole in smaller cube
 pseudoforest – Graph with one cycle per component
 Pythagorean tiling – Tiling by squares of two sizes
 quadrisecant – Line through four points of a curve
 Rado graph – Infinite graph containing all countable graphs
 regular number – Numbers that evenly divide powers of 60
 Reuleaux triangle – Curved triangle with constant width
 reversible cellular automaton – Cellular automaton that can be run backwards
 rook's graph – Graph of chess rook moves
 Klaus Roth – British mathematician
 Rule 90 – Elementary cellular automaton
 Rule 184 – Elementary cellular automaton
 Schwarz lantern – Nearcylindrical polyhedron with large area
 Shapley–Folkman lemma – Sums of sets of vectors are nearly convex
 snark (graph theory) – 3regular graph with no 3edgecoloring
 squaredifferencefree set – Numbers whose differences are not squares
 square pyramidal number – Number of stacked spheres in a pyramid
 squaring the circle – Problem of constructing equalarea shapes
 Stars (M. C. Escher) – Wood engraving print by M. C. Escher
 Steinitz's theorem – Graphtheoretic description of polyhedra
 Carl Størmer – Norwegian geophysicist and mathematician
 Sylvester–Gallai theorem – Existence of a line through two points
 Sylvester's sequence – Doubly exponential integer sequence
 telephone number (mathematics) – Number of ways to pair up n objects
 Theil–Sen estimator – Statistical method for fitting a line
 threegap theorem – On distances between points on a circle
 three utilities problem – Mathematical puzzle of avoiding crossings
 triaugmented triangular prism – Convex polyhedron with 14 triangle faces
 Turán's brick factory problem – On minimizing crossings in bicliques
 2satisfiability – Logic problem, AND of pairwise ORs
 Unit distance graph – Geometric graph with unit edge lengths
 Unit fraction – One over a whole number
 Viète's formula – Infinite product converging to 2/π
 widest path problem – Pathfinding using highweight graph edges
 witch of Agnesi – Cubic plane curve
 X + Y sorting – Problem of sorting pairs of numbers by their sum
 YBC 7289 – Ancient Babylonian clay tablet
 Znám's problem – On divisibility among sets of integers
See also[edit]
 Stuff I've changed, other stuff I've done stuff to, and stuff I'd like to do
 Featured pictures (as nominator, not creator): Bill Hosokawa at the Heart Mountain Relocation Center, Street Musicians at the Door
 Spiky things
Boxicity[edit]
This user is a member of WikiProject Mathematics. 
CS  This user is a member of WikiProject Computer science. 
This user is a member of WikiProject Academic Journals. 
This user is a member of WikiProject Women in Red (redlinks→blue) 
This user teaches at a university or other institution of higher education. 
OC  This user lives in Orange County, California. 
they  This user considers singular they standard English usage. 
,  This user fixes commasplices; they are annoying. 
This user is an administrator on the English Wikipedia. (verify) 
This user has been a member of Wikipedia since August 2006. 
This user contributes images to Wikimedia Commons. 
 Wikipedia administrators
 WikiProject Mathematics members
 Wikipedians interested in mathematics
 WikiProject Computer science participants
 Wikipedians interested in computer science
 WikiProject Women in Red members
 Wikipedian university teachers
 Wikipedians in Orange County, California
 Wikipedians who contribute to Wikimedia Commons
 Wikipedian mathematicians
 Wikipedian computer scientists
 Wikipedians who have access to JSTOR