# Proof Gallery

- Computing Percentages Easier

September 5, 2023 - A parlor trick for SET

March 25, 2018 - A Spectral Analysis of Moore Graphs

November 3, 2016 - Methods of Proof — Diagonalization

June 8, 2015 - Learning a single-variable polynomial, or the power of adaptive queries

November 18, 2014 - A Rook Game

August 31, 2014 - Cauchy-Schwarz Inequality (and Amplification)

July 23, 2013 - Ramsey Number Lower Bound

December 2, 2012 - There are Infinitely Many Primes (Erdős)

November 10, 2012 - Double Angle Trigonometric Formulas

May 19, 2012 - False Proof – 2 = 4, As the Limit of an Infinite Power Tower

May 5, 2012 - Classic Nintendo Games are NP-Hard

March 22, 2012 - Fundamental Theorem of Algebra (With Picard's Little Theorem)

February 7, 2012 - The Fundamental Theorem of Algebra (with Galois Theory)

February 2, 2012 - Handshake Lemma

January 29, 2012 - The Fundamental Theorem of Algebra (with the Fundamental Group)

January 22, 2012 - The Fundamental Theorem of Algebra (with Liouville)

January 17, 2012 - Tiling a Chessboard with Dominoes (Opposite Colors Removed)

November 18, 2011 - Z[√2] has Infinitely Many Units

November 7, 2011 - False Proof: 1 = 2 (with Calculus)

October 25, 2011 - The Smallest Non-Cyclic Simple Group has Order 60

October 8, 2011 - N Choose 2 is the Sum of the First N-1 Integers

October 2, 2011 - n-Colorability is Equivalent to Finite n-Colorability (A Formal Logic Proof)

September 4, 2011 - The Square Root of 2 is Irrational (Geometric Proof)

August 14, 2011 - False Proof—All Numbers are Describable in at Most Twenty Words

July 28, 2011 - Möbius Transformations are Isometries of a Sphere

July 23, 2011 - False Proof—The Reals are Countable

July 19, 2011 - False Proof—All Horses are the Same Color

July 16, 2011 - Three Circles and Collinear Centers of Dilation

July 13, 2011 - False Proof—31.5 = 32.5

July 7, 2011 - False Proof—There are Finitely Many Primes

July 5, 2011 - False Proof—1 = 2

July 5, 2011 - Geometric Series with Geometric Proofs

July 5, 2011 - Sums of k Powers

July 1, 2011 - Tiling a Chessboard

June 26, 2011 - Area of a Triangle

June 24, 2011 - Sums of the first n numbers, squares

June 24, 2011 - The Party Problem

June 23, 2011 - Number of Games in a Tournament

June 23, 2011