Broken Hyperlinks
The following URLs no longer point to valid pages. The pages may have moved, or they may have vanished. Any assistance in providing additional information as to the current location of the following items would be greatly appreciated. Please send updates to the MathWorld team
AKS Primality Test: (2007-12-13) Indian Institute of Technology. "PRIMES is in P." http://www.cse.iitk.ac.in/news/primality.html
Arbelos: (2005-07-22) Woo, P. "The Arbelos." http://www-students.biola.edu/~woopy/math/arbelos.htm
B-Line: (2003-02-25) Todd, A. "Bisecting a Triangle." http://www.math.colostate.edu/~todd/triangle.html
Barth Sextic: (2003-02-26) Dominici, P. "Flight Through Barth's Sextic." http://www.mi.uni-erlangen.de/~bauerth/flight/
Bordism: (2003-02-25) Budney, R. "The Bordism Project." http://www.math.cornell.edu/~rybu/bordism/bordism.html
Boy Surface: (2000-07-09) Wang, P. "Renderings." http://www.ugcs.caltech.edu/~peterw/portfolio/renderings/
Brier Number: (2008-08-09) McLean, J. "Brier Numbers." http://www.glasgowg43.freeserve.co.uk/brier2.htm
Circle Packing: (2007-11-01) Boll, D. "Packing Results." http://www.frii.com/~dboll/packing.html
Circle Packing: (2003-02-25) Nurmela, K. J. and Östergård, P. R. J. packings/square/. http://www.tcs.hut.fi/packings/square/
Combinatorics: (1999-12-06) Coolsaet, K. "Index of Combinatorial Objects." http://gonzo.hogent.be/~kc/ico/
Complexity Theory: (2003-03-12) Goetz, P. "Phil Goetz's Complexity Dictionary." http://www.cs.buffalo.edu/~goetz/dict.html
Coxeter's Loxodromic Sequence of Tangent Circles: (2006-02-14) Coxeter, D. "Coxeter on 'Firmament.' " http://www.bangor.ac.uk/SculMath/image/donald.htm
Cube: (2011-04-26) Hidekazu, T. "Research on a Cube." http://www.biwako.ne.jp/~hidekazu/materials/cubee.htm
Cyclide: (1998-10-08) Bierschneider-Jakobs, A. "Cyclides." http://www.mi.uni-erlangen.de/~biersch/cyclides.html
Cycloid: (2003-02-25) Muterspaugh, J.; Driver, T.; and Dick, J. E. "The Cycloid and Tautochronism." http://php.indiana.edu/~jedick/project/intro.html
Diophantine Equation--6th Powers: (2003-02-25) Resta, G. "New Results on Equal Sums of Sixth Powers." Instituto di Matematica Computazionale, Pisa, Italy. April 1999. http://www.chez.com/powersum/Tr-b4-08.zip
Domino: (2003-02-25) Lei, A. "Domino." http://www.cs.ust.hk/~philipl/omino/domino.html
Egyptian Fraction: (1998-02-14) Gardner, M. "Babylonian and Egyptian Mathematics, an Egyptian Historical Gap, Installments 1-3." http://www.teleport.com/~ddonahue/phresour.html
Fibonacci Number: (2003-02-25) Leyland, P. ftp://sable.ox.ac.uk/pub/math/factors/fibonacci.Z
Flexagon: (2000-07-09) Conrad, A. S. and Harline, D. K. "Flexagons." TR 62-11, May 1962. http://delta.cs.cinvestav.mx/~mcintosh/newweb/new.html
Flower of Life: (2003-02-25) Wein, J. "La Fleur de Vie." http://www2.cruzio.com/~flower/fleur.htm
Game of Life: (1999-11-15) McIntosh, H. V. "Life." http://www.cs.cinvestav.mx/mcintosh/oldweb/life.html
Goblet Illusion: (1998-02-01) "Reversible Goblet." http://www.nari.ee.ethz.ch/nari_lectures/bildkom/Studenten_Projekte/Sommer96/Projekt5/sub1/goblet.html
Goblet Illusion: (1999-12-06) What's Up with Kids Magazine. "Reversible Goblet." http://wuwk.spurtek.com/COI_reversible_goblet.htm
Haberdasher's Problem: (1999-12-06) Chuan, J. C. "Geometric Construction." http://www.math.ntnu.edu.tw/gc/chuan/gc.html
Heptadecagon: (2000-07-09) Wang, P. "The Regular Heptadecagon." http://www.ugcs.caltech.edu/~peterw/studies/17gon/
Hexiamond: (2000-07-09) Paulhus, M. "The Hexiamond Home Page." http://www.math.ucalgary.ca/~paulhusm/hexiamond1/
Hilbert Curve: (2003-03-12) Goetz, P. "Phil Goetz's Complexity Dictionary." http://www.cs.buffalo.edu/~goetz/dict.html
Icosahedron Stellations: (2000-07-09) Wang, P. "Polyhedra." http://www.ugcs.caltech.edu/~peterw/portfolio/polyhedra/
Josephus Problem: (2005-09-13) Smith, H. J. "Josephus Permutation Problems." http://www.geocities.com/hjsmithh/Josephus.html
Knight Graph: (2012-12-15) Jelliss, G. "Knight's Tour Notes." http://www.ktn.freeuk.com/
Knight Graph: (2012-12-15) Jelliss, G. "Chronology of Knight's Tours." http://www.ktn.freeuk.com/cc.htm
Knot: (1997-08-18) Zia. "Zia Knotting." http://204.30.30.10/hac/knots/
Kolmogorov Complexity: (2003-03-12) Goetz, P. "Phil Goetz's Complexity Dictionary." http://www.cs.buffalo.edu/~goetz/dict.html
Lucas Number: (2003-02-25) Leyland, P. ftp://sable.ox.ac.uk/pub/math/factors/lucas.Z
Machin-Like Formulas: (2009-03-10) Williams, R. "Arctangent Formulas for Pi." http://www.cacr.caltech.edu/~roy/upi/pi.formulas.html
Magic Circles: (1999-12-06) Hung, K. M. "Magic Circle." http://home.hkstar.com/~hkm88630/magiccl.html
Magic Cube: (2003-02-25) Lei, A. "Magic Cube and Hypercube." http://www.cs.ust.hk/~philipl/magic/mcube2.html
Magic Square: (2003-02-25) Lei, A. "Magic Square, Cube, Hypercube." http://www.cs.ust.hk/~philipl/magic/
Magic Tour: (2012-12-15) Jelliss, G. "Knight's Tour Notes." http://home.freeuk.net/ktn/
Magic Tour: (2012-12-15) Jelliss, G. "General Theory of Magic Knight's Tours." http://home.freeuk.net/ktn/mg.htm
Matchstick Graph: (2022-01-03) Timm, M. "Diskrete Mathematik." http://www.mathematik.tu-bs.de/dm/
Möbius Strip: (1997-04-16) Dickau, R. "Spinning Möbius Strip Movie." http://mathforum.org/advanced/robertd/moebius.html
Möbius Strip: (2000-07-09) Wang, P. "Renderings." http://www.ugcs.caltech.edu/~peterw/portfolio/renderings/
Multiperfect Number: (1996-10-07) Perrier, J.-Y. "The Multi-Perfect Numbers." http://diwww.epfl.ch/~perrier/Multiparfaits.html
Narcissistic Number: (2000-07-09) Corning, T. "Exponential Digital Invariants." http://members.aol.com/tec153/Edi4web/Edi.html
Nevanlinna Prize: (2008-05-06) International Congress of Mathematics. "Rolf Nevanlinna Prize." http://www.icm2002.org.cn/general/prize/nevanlinna.htm International Mathematical Union. "Fields Medals and Rolf Nevanlinna Prize." http://www.mathunion.org/medals/.
Oloid: (2003-02-26) Capocasa, C. "Oloid." http://www.blackpoint.net/capocssa/oloid.html
Pentomino: (2003-02-26) Lei, A. "Pentominoes." http://www.cs.ust.hk/~philipl/omino/pento.html
Pi: (2003-02-25) Plouffe, S. "1 Billion Digits of Pi." http://pi.lacim.uqam.ca/eng/
Pi Digits: (2003-02-25) Kanada, Y. "Our Latest Record." Sep. 20, 1999. ftp://www.cc.u-tokyo.ac.jp/README.our_latest_record
Poggendorff Illusion: (2003-02-25) IllusionWorks. "Poggendorf [sic]." http://www.illusionworks.com/html/poggendorf.html
Polyomino: (2003-02-25) Lei, A. "Bigger Polyominoes." http://www.cs.ust.hk/~philipl/omino/bigpolyo.html
Polyomino: (2003-02-25) Lei, A. "Polyominoes." http://www.cs.ust.hk/~philipl/omino/omino.html
Primorial Prime: (2003-02-25) Leyland, P. ftp://sable.ox.ac.uk/pub/math/factors/primorial-.Z
Prisoner's Dilemma: (2003-03-12) Goetz, P. "Phil Goetz's Complexity Dictionary." http://www.cs.buffalo.edu/~goetz/dict.html
Quadric: (2003-02-25) Takahashi, H. "Quadrica Page." http://www2.kawase-h.ed.jp/Teachers/~Takahashi/Quadrica.html
Qubic: (2005-08-06) Allis, L. V. "Qubic." http://www.cs.vu.nl/~victor/qubic.html
Real Number: (2003-02-25) Shamos, M. I. A Catalog of Real Numbers. In preparation? http://www.ecom.cmu.edu/people/faculty/mshamos/resshort.htm
Roman Surface: (2000-07-09) Wang, P. "Renderings." http://www.ugcs.caltech.edu/~peterw/portfolio/renderings/
RSA Number: (2003-02-25) Leyland, P. ftp://sable.ox.ac.uk/pub/math/rsa129
Semimagic Square: (2012-12-15) Jelliss, G. "Knight's Tour Notes." http://home.freeuk.net/ktn/
Semimagic Square: (2012-12-15) Jelliss, G. "General Theory of Magic Knight's Tours." http://home.freeuk.net/ktn/mg.htm
Sierpiński Sieve: (2000-07-09) Wang, P. "Renderings." http://www.ugcs.caltech.edu/~peterw/portfolio/renderings/
Singular Integral: (2004-09-28) Paulino, G. H. "Singular Integrals." Fall 2001. http://cee.ce.uiuc.edu/paulino/BEM/handouts/sing.pdf
Spherical Code: (2011-03-18) Friedman, E. "Points on a Sphere." http://www.stetson.edu/~efriedma/ptsphere/
Spikey: (2018-12-07) Bell, R. "Spiky: The Temple of Archimedes." http://www.zomadic.com/spiky/
Steinbach Screw: (2000-07-09) Naylor, B. "Steinbach Screw 1." http://www.garlic.com/~bnaylor/raytrace/rtstein1.html
Steinbach Screw: (2000-07-09) Wang, P. "Renderings." http://www.ugcs.caltech.edu/~peterw/portfolio/renderings/
Surface: (2003-02-25) Endraß, S. "Home Page of S. Endraß." http://www.mathematik.uni-mainz.de/~endrass/
Tautochrone Problem: (2003-02-25) Muterspaugh, J.; Driver, T.; and Dick, J. E. "The Cycloid and Tautochronism." http://php.indiana.edu/~jedick/project/intro.html
Tautochrone Problem: (2003-02-25) Muterspaugh, J.; Driver, T.; and Dick, J. E. "P221 Tautochrone Problem." http://php.indiana.edu/~jedick/project/project.html
Templar Magic Square: (1998-11-12) Heietala, H. "The Templar Magic Square." http://www.trantex.fi/staff/heikkih/knights/pubsator.htm
Tetrahedron 5-Compound: (2000-07-09) Wang, P. "Renderings." http://www.ugcs.caltech.edu/~peterw/portfolio/renderings/
Tit-for-Tat: (2003-03-12) Goetz, P. "Phil Goetz's Complexity Dictionary." http://www.cs.buffalo.edu/~goetz/dict.html
Triomino: (2003-02-25) Lei, A. "Tromino." http://www.cs.ust.hk/~philipl/omino/tromino.html
Tutte 8-Cage: (2022-10-31) Royle, G. "F030A." http://www.csse.uwa.edu.au/~gordon/foster/F030A.html
Tutte 8-Cage: (2022-10-31) Royle, G. "Cubic Cages." http://school.maths.uwa.edu.au/~gordon/remote/cages/
Vampire Number: (2008-12-25) Schneider, W. "Vampire Numbers." http://wschnei.de/digit-related-numbers/vampire.html Sloane, N. J. A. Sequences A014575, A048933, A048934, A048935, A048936, A048937, A048938, and A048939 in "The On-Line Encyclopedia of Integer Sequences."
Whitney Umbrella: (2000-07-09) Geometry Center. "Whitney's Umbrella." http://www.geom.umn.edu/zoo/features/whitney/
Zipf's Law: (2003-03-12) Goetz, P. "Phil Goetz's Complexity Dictionary." http://www.cs.buffalo.edu/~goetz/dict.html
Zöllner's Illusion: (2003-02-25) IllusionWorks. "Poggendorf [sic]." http://www.illusionworks.com/html/poggendorf.html
Zöllner's Illusion: (2003-02-25) IllusionWorks. "Zollner." http://www.illusionworks.com/html/zollner.html