Theorem of the Day  

Complete Theorem Listing by Thumbnail

As in the main theorem list the list is presented here in reverse chronological order, so that new additions will appear at the top.

Clicking on an image will take you directly to the pdf of the theorem page; clicking on the name text will take you to the theorems listing in the main index.

1.    Kőnig's Infinity Lemma
2.    The Pigeonhole Principle
3.    The Hockey Stick Identity
4.    Moessner's Magic
5.     Wolstenholme's Inequality
6.    The Catalan–Euler–Segner Bijection
7.    Cramer's Rule
8.    The Intermediate Value Theorem
9.    Turing-completeness of Conway's Game of Life
10.    Bondy's Subset Theorem
11.    Tunnell's Theorem
12.    The Shoelace Formula
13.    The Polygonal Number Theorem
14.    Euclid's Pythagorean Formula
15.    Dunn and Pretty's Triangle-Halving Deltoid
16.    Schur's Commuting Matrices Bound
17.    Sylow's Theorems
18.    Distribution of Local Maxima in Random Samples
19.    Moreau's Necklace Formula
20.    Countability of the Rationals
21.    Kasteleyn's Theorem
22.    The Third Isomorphism Theorem
23.    Bertrand's Ballot Theorem
24.    The Hanani–Tutte Theorem
25.    The Power of a Point Theorem
26.    Bézout's Identity
27.    A Theorem about Gaussian Moats
28.    Euler's Product Formula for Sine
29.    Euler's Product Formula for ζ(s)
30.    The Alternating Series Test
31.    The LYM Inequality
32.    A Theorem of Anderson, Cameron and Preece on Groups of Units
33.    The Pólya–Redfield Enumeration Theorem
34.    The Large Prime Gaps Theorem
35.    The Jones Knot Polynomial Theorem
36.    Kuratowski's 14-Set Theorem
37.    Euler's Even Zeta Formula
38.    Sylvester's Catalecticant
39.    Kemeny's Constant
40.    A Theorem on Modular Fibonacci Periodicity
41.    A Generalised Hlawka Inequality
42.    The Circle Area Theorem
43.    The Riemann Explicit Formula
44.    Sophie Germain's Identity
45.    Ore's Theorem in Graph Theory 
46.    Poncelet's Porism
47.    Fisher's Inequality
48.    Cauchy's Theorem in Group Theory
49.    Wolstenholme's Theorem
50.    The Spherical Law of Cosines
51.    Green's Theorem
52.    Tutte's Golden Identity
53.    Faulhaber's Formula
54.    The Inclusion-Exclusion Principle
55.    The Pappus–Guldin Theorems
56.    Integration by Parts
57.    The Riemann Rearrangement Theorem
58.    Taylor's Theorem
59.    Irrationality of Circumference of Unit Circle
60.    Wedderburn's Little Theorem
61.    A Theorem on Maximal Sum-free Sets in Groups
62.    The 6-Circles Theorem
63.    Vizing's Theorem
64.    Willans' Formula
65.  The Basel Problem
66.    The Erdős Discrepancy Problem
67.    Toricelli's Trumpet
68.    The Eratosthenes-Legendre Sieve
69.    Euler's Formula
70.    The Classification of the Semiregular Tilings
71.    Singmaster's Binomial Multiplicity Bound
72.    Euler's Continued Fraction Correspondence
73.    The Friedlander–Iwaniec Theorem
74.    Jensen's Inequality
75.    Minkowski's Convex Body Theorem
76.    Fermat's Two-Squares Theorem
77.    The Art Gallery Theorem
78.    The Robin–Lagarias Theorem
79.    The Cantor–Bernstein–Schröder Theorem
80.    The Erdős–Ko–Rado Theorem
81.    Wilson's Theorem
82.    Frieze's Theorem on Expected Minimum Tree Length
83.    The Rotation Distance Bound
84.    L'Hospital's Rule
85.    Jackson's Theorem on Compatible Euler Tours
86.    The Handshaking Lemma
87.    al-Kāshi's Law of Cosines
88. Karp's Theorem (Detail)
89.    The Insolvability of the Entscheidungsproblem
90.    Kőnig's Bipartite Matching Theorem
91.    von Neumann's Minimax Theorem
92.    Theorema Egregium
93.    The Girard–Newton Identities
94.    Archimedes' Equiareal Map Theorem
95.    The Greibach Normal Form Theorem
96.    The Descartes Circle Theorem
97.    Sendov's Conjecture
98.    The Heine–Borel Theorem
99.    The Existence Theorem for Bachelor Latin Squares
100.    The Bungers–Lehmer Theorem on Cyclotomic Coefficients
101.    The Cameron–Fon-Der-Flaass IBIS Theorem
102.    The Ramanujan Partition Congruences
103.    The Andrews–Garvan–Dyson Crank
104.    The BEST Theorem
105.    Machin's Formula
106.    Sokal's Theorem on Chromatic Roots
107.    The Max-Flow Min-Cut Theorem
108.    The Lindemann–Weierstrass Theorem
109.    Haken's Unknot Theorem
110.    Lin McMullin's Theorem
111.    The Diaconis–Holmes–Montgomery Coin Tossing Theorem
112.    The Friendship Theorem
113.    Heath's Finitely Discontinuous Function Theorem
114.    Quadratic Nonresidue is Zero-Knowledge Provable
115.    The Classification of Archimedean 4-Polytopes
116.    The McIver–Neumann 1/2-n Bound
117.    The Albert–Brauer–Hasse–Noether Main Theorem
118.    The Transversal Matroid Theorem
119.    The Lecture Hall Partition Theorem
120.    A Tripartite Turán Theorem
121.    The Remainder Theorem
122.    Euler's Partition Identity
123.    De Moivre's Theorem
124.    The Small Prime Gaps Theorem
125.    Woodall's Hopping Lemma
126.    Euclid's Triangular Prism
127.    A Theorem of Schur on Real-Rootedness
128.    The Sophomore's Dream
129.    The Panarboreal Formula
130.    The Contraction Mapping Theorem
131.    Lieb's Square Ice Theorem
132. The Robinson–Schensted–Knuth Correspondence
133.    Sylvester's Law of Inertia
134.    The Piff–Welsh Theorem
135.    A Theorem on Rectangular Tensegrities
136.    Strassen's Matrix Theorem
137.    Vaughan Pratt's Theorem
138.    Wallis's Product
139.    Theorems of Euler and Rényi on 'e'
140.    Praeger's Theorem on Bounded Movement
141.    The Change of Variables Theorem
142.    The Total Probability Theorem
143.    Theaetetus' Theorem on the Platonic Solids
144.    The Existence Theorem for Orthogonal Diagonal Latin Squares
145.    A Theorem on Apollonian Circle Packings
146.    The Ollerenshaw–Brée Formula
147.    The Euclid–Euler Theorem
148.    The Lucas–Lehmer Test
149.    The Asymptotic (Half) Liar Formula
150.    The Skolem–Noether Theorem
151.    The Lagrange Interpolation Formula
152.    The Wedderburn–Artin Theorem
153.    The Borsuk–Ulam Theorem
154.    Lambert's Formula
155.    The Lovász Local Lemma
156.    Kneser's Conjecture
157.    Catalan's Conjecture (Mihăilescu's Theorem)
158.    A Theorem of Erdős and Wilson on Edge Colouring
159.    The Polynomial Coprimality Theorem
160.    The Hardy–Ramanujan Asymptotic Partition Formula
161.    The Lagrange Property for Moufang Loops
162.    van der Waerden's Conjecture
163.    Bregman's Theorem
164.    De Morgan's Laws
165.    The Robbins Problem
166.    The Beardwood–Halton–Hammersley Theorem
167.    The Analyst's Travelling Salesman Theorem
168.    The Tverberg Partition Theorem
169.    Babbitt's Theorem
170.    The Pumping Lemma
171.    The Goins–Maddox–Rusin Theorem on Heron Triangles
172.    The Parking Function Formula
173.    Viète's Formula
174. Kepler's Conjecture
175.    The Design of the Century
176.    The Happy Ending Problem
177.    Cartwright's Theorem
178.    Nevanlinna's Five-Value Theorem
179.    The Rule of Sarrus
180.    The Convolution Theorem
181.    Cayley's Formula
182.    The Generalised Hexachord Theorem
183.    The Quadratic Formula
184.    Khinchin's Theorem on Continued Fractions
185.    Cardano's Cubic Formula
186.    The Abel–Hurwitz Binomial Theorem
187.    The Cauchy–Kovalevskaya Theorem
188.    Lamé's Theorem
189.    Noether's Symmetry Theorem
190.    Cayley's Theorem
191.    The Five Circle Theorem
192.    The Delsarte–Goethals–Seidel Theorem
193.    Gruenberg's Theorem on Nilpotent Groups
194.    The Lutz–Nagell Theorem
195.    1-Factorisation of Regular Graphs
196.    The Fifteen Theorem
197.    The Three-Distance Theorem
198.    Pick's Theorem
199.    Brahmagupta's Formula
200.    Gödel's Second Incompleteness Theorem
201.    Gödel's First Incompleteness Theorem
202.    Goodstein's Theorem
203.    MacWilliams' Identity
204.    Sharkovsky's Theorem
205.    The 1-2-3 Conjecture
206.    Arrow's Impossibility Theorem
207.    The Stable Marriage Theorem
208.    Reidemeister's Theorem
209.    An Erdős–Ko–Rado Theorem on Intersecting Permutations
210.    The Sims Conjecture
211.    Neumann's Separation Lemma
212.    Thales' Theorem
213.    The Marriage Theorem and The Frobenius–Kőnig Theorem
214.    Moufang's Theorem
215.    The Strong Perfect Graph Theorem
216.    Germain's Theorem
217.    Galois' Theorem on Finite Fields
218.    The Birkhoff–von Neumann Theorem
219.    Morley's Miracle
220.    Miquel's Triangle Theorem
221.    The Bose Equivalence Theorem in Design Theory
222.    Bailey's Theorem on Latin Squares
223.    The Robertson–Seymour Graph Minors Theorem
224.    A Theorem of Melody Chan on Group Actions
225.    The Euler–Hierholzer "Bridges of Königsberg" Theorem
226.    Netto's Conjecture (Dixon's Theorem)
227.    Beineke's Theorem on Line Graphs
228.    The Binomial Theorem
229.    Cameron's Theorem on Distance-Transitive Graphs
230.    Binet's Formula
231.    Pappus' Theorem
232.    The DPRM Theorem
233.    Zeckendorf's Theorem
234.    Lagrange's Theorem
235.    Stirling's Approximation
236.  Pascal's Rule
237.    Lucas' Theorem
238.    Girard's Theorem
239.    Euler's Identity
240.    The Second Isomorphism Theorem
241.    The First Isomorphism Theorem
242.    The Prime Number Theorem
243.    The Green–Tao Theorem on Primes in Arithmetic Progression
244.    Benford's Law
245.    The Law of Large Numbers
246.    Gauss's Law of Quadratic Reciprocity
247.    Ramsey's Theorem
248.    The Pythagorean Theorem
249.    Euler's Polyhedral Formula
250.    Wagner's Theorem
251.    Kuratowski's Theorem
252.    Cantor's Theorem
253.    Cantor's Uncountability Theorem
254.    Brun's Theorem
255.    The Merton College Theorem
256.    Dilworth's Theorem
257.    Brouwer's Fixed Point Theorem
258.    The Well-Ordering Theorem
259.    Sperner's Lemma
260.    The Cauchy–Frobenius Lemma
261.    Cook's Theorem on NP-completeness
262.    Fermat's Little Theorem
263.    The Matrix Tree Theorem
264.    Lagrange's Four-Squares Theorem
265.    Bayes' Theorem
266.    Fermat's Last Theorem
267.    The Central Limit Theorem
268.    The Fundamental Theorem of Arithmetic
269.    The Fundamental Theorem of Algebra
270. The Chinese Remainder Theorem
271. Euclid's Infinity of Primes
272.    The Bruck–Ryser–Chowla Theorem on Finite Projective Planes
273.    The Fundamental Theorem of the Calculus
274.    The Four-Colour Theorem