articles, collections

Here I am gonna posts geometry  articles, notes  and problem collections,  that I create or collect from sites around the internet (except the Tournament Of Towns Conferences). All the aother articles, are also in the other pages. Free books, old and recent, are collected here.

Paris Pamfilos - Geometricon
190 pages' Sample of Geometricon, a 800 pages Geometry book in English, currently available only in Greek                        (his homepage , source of this file)

Problems collections by others, from the internet

• Abdilkadir Altıntaş & Ercole Suppa - Sangaku problems
• Amir Hossein Parvardi - (25) Geometry Problems (January 6, 2011) <solved in links>
• Amir Hossein Parvardi - 150 Nice Geometry Problems (January 9, 2011) <solved in links>
• Amir Hossein Parvardi - 60 Geometry Problems (October 13, 2011) <solved in links>
• David Altisio - 100 Geometry problems (August 30 2014) 
• David Altisio - 100 Geometry problems, Solutions edited by Alvin Zou (April 26 2015)  (source)
• Ercole Suppa - Geometry Marathon (Mathlinks Forum, July 14, 2012) <521 solved in links>
• Liverpool26 - 111 Nice Geometry Problems from Mathscope (January 01,2013) (source)
• Tran Quang Hung - Red Geometry <118 unsolved>

Notable geometry articles

• Alexander Skutin - Some new theorems in plane geometry
• Alexander Skutin - Creative Geometry
• Alexander Skutin - Cosmology of Plane Geometry 2021 version (contains problems by Tran Quang Hung, Kadir Altintas and Antreas Hatzipolakis) (intro)
• Milton Donaire Peña - Area Poligonal 2020 (no7)
• Milton Donaire Peña - Region-Cuadrangular (no6).

Non English problem collections

• Geometri Günlüğü 001-500 (Turkish) by Abdilkadir Altıntaş
• Geometri Günlüğü 501-849 (Turkish) by Abdilkadir Altıntaş

Tran Viet Hung (collected here) FB account

• 001-200 Mixtilinear problems      (Vietnamese)  BaiMixtilinear
• 201-400 Mixtilinear problems      (Vietnamese)
• 401-600 Mixtilinear problems      (Vietnamese / English >= 436)
• 601-800 Mixtilinear problems      (English)
• 801-1000 Mixtilinear problems    (English)
• 1001-1200 Mixtilinear problems  (English)
• 1201-1400 Mixtilinear problems  (English)
• 001-200 PhuTruong problems      (Vietnamese / English >= 120)  BaiPhuTruong
• 201-400 PhuTruong problems      (English)
• 401-600 PhuTruong problems      (English)
• 601-800 PhuTruong problems      (English)
• 801-1000 PhuTruong problems    (English)

Concurrent lines, problems without words

Hans Walser - Schnittpunkte :  (collected here)

101-200 ,  201-300 ,  301-400 ,   401-500 ,  501-600,  601-700 ,  701-800 , 801-900

source: www.walser-h-m.ch/hans/ 

problem collections that do not contain only geometry

• Original Problems Proposed by Stanley Rabinowitz 1963–2005 (Math-Pro Press 2006)
• Mathscope, All the best from Vietnamese Problem Solving Journals (f40)  (a collection of problems selected from Vietnamese math journals (particularly Mathematics and the Youth from the last 10 years), compiled by Phạm Vǎn Thuận. At this moment it contains 424 problems. Updated: February 12, 2007)
• Collection of Inequalities (f41) (a collection of inequalities published in various math journals (a majority in Crux Mathematicorum) and books, compiled by Eckard Specht. At this moment it contains 1454±ε problems. Updated: October 22, 2006)

sources:
analgeomatica.wordpress.com  (Tran Quang Hung)
artofproblemsolving.com  (Amir Hossein Parvardi, David Altisio, Ercole Suppa)
mathscope.org  (liverpool26)
www.imomath.com (mathscope, collection of inequalities)
The School Yard Olympiad facebook group (Geometri Günlüğü)


My problem collections in English

• 397 geometry problems from  Sobregeometrias SX SG
• 345 geometry problems from 8floxes.com  
• 259 geometry writings by Christopher J. Bradley
• 127 geometry problems from fb group JUVENTUD GEÓMETRA (2nd edition)
• 50 geometry problems from fb group JUVENTUD MATEMÁTICA

sources:

8foxes.blogspot.com (blogspot, inactive)

JUVENTUD GEÓMETRA (fb group, incactive)

JUVENTUD MATEMÁTICA (fb group, incactive)

Geito Mr.G - SobreGeometrias (blogspot, incactive)

sites.google.com/a/8foxes.com/www/ (blogspot, inactive)

Sobre Geometrias SG SX (wordpress, incactive)

Sobre Geometrias SG (fb page, incactive)

Sobre Geometrias SG SX (fb group, incactive)

people.bath.ac.uk/masgcs/bradley.html (Bradley)

Of Historic Value

• Elisha Scott Loomis -  The Pythagorean Proposition (2nd ed.1940, 285 pages) <370 proofs>  

• McDonald Kirk - A solution to the problem of Apollonius (19 May 1964)

Geometric Transformations

• Evan Chen - Euclidean Geometry in Mathematical Olympiads, Chapter 8 - Inversion
• Kenji Kozai & Shlomo Libeskind - Circle Inversions and Applications to Euclidean Geometry (January 9, 2009)
• Tom Davis - Inversion in a Circle (March 23, 2011)
• Zvezdelina Stankova - Inversion in the plane (September 26 2004)  
• Unknown - An Introduction to Projective Geometry, 06-10-21_Geom2006_2 (based on Yaglom's Geometric Transformations)

Articles - Notes 

• Dominik Teiml - The Euler Line, proofs, properties, and applications (May 2013)
• J. Marshall Unger - A collection of 30 Sangaku problems (12 Jan16)
• Heather Macbeth - Collinearity and Concurrence (22 March 2009) (Deputy Team Leader for New Zealand)
• Po-Shen Loh - Collinearity And Concurrence  (23 June 2008) (Deputy Team Leader for the United States)
• Quines Joshua Carl - Pascal's Τheorem  (5 Jan 2017)
• Nicula Virgil , Pohoata Cosmin - A Stronger Form of the Steiner-Lehmus Theorem (Journal for Geometry and Graphics , Volume 13 (2009), No. 1, 25–27)
• Pohoata Cosmin - Harmonic quadrilaterals revisited (Gazeta Marematica, Seria A, Nr. 1 -2.2011)
• Rapanos Nikolaos - The complete quadrilateral and its properties (July 7, 2009)
• Rapanos Nikolaos - The harmonic quadrilateral and its properties (July 7, 2009)
• Richter- Gebert J. - Pappus’s Theorem: Nine Proofs  and Three Variations (2011)
• Suppa Ercole - Divisione Armonica (17-20 October 2010) (Italian)
• Victoria Krakovna - Concurrency and Collinearity (2010) (Deputy Leader for Canada)
• Vipul Naik - Co-Incidense Problems And Methods (India IMO Training Camp)
• Zarathustra Brady - Some cross ratios (written for high school students) 

Barycentric Coordinates

from International Journal of Computer Discovered Mathematics (www.journal-1.eu)

• Francisco Javier García Capitán -Barycentric Coordinates   (Vol.0 2015 pp.32-48)
• Francisco Javier García Capitán - Posing and Solving Problems with Barycentric Coordinates,  (Vol.1. No.1. 2016 pp.36-44)
• S. Grozdev and D. Dekov - Barycentric Coordinates: Formula Sheet, (Vol.1. No.2. 2016 pp.75-82)

Geometry articles from IJAAMM (The International Journal of Advances in Applied Mathematics and Mechanics)

(collected here)

Geometry articles from: RMM  (Romanian Mathematical Magazine)

(collected here)

Geometry Articles by Mathematical Excalibur

(collected here)

Geometry Articles  by  Revista Escolar de la Olimpíada Iberoamericana de Matemática

(collected here)

Geometry material from Canada IMO Training Site

                                                                     (collected here) 

attention old links below, might be dead

Finally

The problems from the Facebook Group Romantics of Geometry in English:

 
plane geometry links in FB: 001-500, 501-1000, 1001-1500 , 1501-2000 , 2000-2500
link in FB: solid geometry

The exercises by the Romantics of Geometry in English (pdf): (not updated anymore)

• 120 geometry exercises by Romantics of Geometry, volume 1, issues 01-10, No 001-120 (12.11.2016) 
• 60 geometry exercises by Romantics of Geometry,  issues 11-15, No 121-180 (08.03.2017)
• 24 geometry exercises by Romantics of Geometry,  issues 36-37, No 421-444 (08.03.2017)
• 12 geometry exercises by Romantics of Geometry,  issue 46, No 541-552 (07.03.2017)