# Angel "Java" Lopez en Blog

### Publicado el 31 de Agosto, 2012, 13:24

 Siguiente Post Geometría es un tema que en este siglo me lo encuentro cada vez más, tanto relacionado con la teoría de grupos, como con teorías físicas. Una primera lista de los enlaces que he visitado. Vean en el fragmento de la Wikipedia, cómo con Descartes la geometría va fusionándose con el álgebra. Gran parte de la búsqueda de simetría en las teorías físicas, es una lucha por volver a lo geométrico, sin depender de sistema de coordenadas o marco de referencia. Visiten también lo que hay sobre el grupo E8. http://en.wikipedia.org/wiki/Geometry Geometry (Ancient Greek: γεωμετρία; geo- "earth", -metron "measurement") is a branch of mathematics concerned with questions of shape, size, relative position of figures, and the properties of space. A mathematician who works in the field of geometry is called a geometer. Geometry arose independently in a number of early cultures as a body of practical knowledge concerning lengths, areas, and volumes, with elements of a formal mathematical science emerging in the West as early as Thales (6th Century BC). By the 3rd century BC geometry was put into an axiomatic form by Euclid, whose treatment—Euclidean geometry—set a standard for many centuries to follow.[1] Archimedes developed ingenious techniques for calculating areas and volumes, in many ways anticipating modern integral calculus. The field of astronomy, especially mapping the positions of the stars and planets on the celestial sphere and describing the relationship between movements of celestial bodies, served as an important source of geometric problems during the next one and a half millennia. Both geometry and astronomy were considered in the classical world to be part of the Quadrivium, a subset of the seven liberal arts considered essential for a free citizen to master. The introduction of coordinates by René Descartes and the concurrent developments of algebra marked a new stage for geometry, since geometric figures, such as plane curves, could now be represented analytically, i.e., with functions and equations. This played a key role in the emergence of infinitesimal calculus in the 17th century. Furthermore, the theory of perspective showed that there is more to geometry than just the metric properties of figures: perspective is the origin ofprojective geometry. The subject of geometry was further enriched by the study of intrinsic structure of geometric objects that originated with Euler and Gauss and led to the creation of topology and differential geometry. In Euclid's time there was no clear distinction between physical space and geometrical space. Since the 19th-century discovery of non-Euclidean geometry, the concept of space has undergone a radical transformation, and the question arose: which geometrical space best fits physical space? With the rise of formal mathematics in the 20th century, also 'space' (and 'point', 'line', 'plane') lost its intuitive contents, so today we have to distinguish between physical space, geometrical spaces (in which 'space', 'point' etc. still have their intuitive meaning) and abstract spaces. Contemporary geometry considers manifolds, spaces that are considerably more abstract than the familiar Euclidean space, which they only approximately resemble at small scales. These spaces may be endowed with additional structure, allowing one to speak about length. Modern geometry has multiple strong bonds with physics, exemplified by the ties between pseudo-Riemannian geometry and general relativity. One of the youngest physical theories, string theory, is also very geometric in flavour. Geometric visual hallucinations http://rstb.royalsocietypublishing.org/content/356/1407/299.full.pdf The Geomblog: Geometry @ Barriers http://geomblog.blogspot.com/2010/09/geometry-barriers.html Geometric algorithmsThe Universe of Discourse : A new proof that the square root of 2 is irrational http://blog.plover.com/math/sqrt-2-new.html Euclides.org http://www.euclides.org George W. Hart http://www.georgehart.com/Geometric sculptures and puzzles The Museum of Mathematics http://momath.org/ Triángulos disjuntos (Puzzle) http://gaussianos.com/triangulos-disjuntos/ Touch Trigonometry http://www.touchtrigonometry.org/ An introduction to the ancient and modern geometry of conics http://openlibrary.org/works/OL7563147W/An_introduction_to_the_ancient_and_modern_geometry_of_conics Superformula http://en.wikipedia.org/wiki/Superformula Pappus chain http://en.wikipedia.org/wiki/Pappus_chain Physics intuitions: Forwards multiplying, backwards dividing http://commonsensequantum.blogspot.com/2011/04/forwards-multiplying-backwards-dividing.html Physics intuitions: Morley triangle derived from the tripling of an angle http://commonsensequantum.blogspot.com/2011/03/morley-triangle-derived-from-tripling.html Physics intuitions: Archimedes angle trisection or tripling? http://commonsensequantum.blogspot.com/2011/03/archimedes-angle-trisection-or-tripling.html Physics intuitions: Playing with angles http://commonsensequantum.blogspot.com/2011/03/playing-with-angles.html Albrecht Dürer"s ruler and compass constructions http://divisbyzero.com/2011/03/22/albrecht-durers-ruler-and-compass-constructions/ PLaSM http://plasm.net/functional language for computing with geometry Manifolds « The Unapologetic Mathematician http://unapologetic.wordpress.com/2011/02/22/manifolds/ La construccion del dodecaedro en los elementos de Euclides http://gaussianos.com/la-construccion-del-dodecaedro-en-los-elementos-de-euclides/ Introduction to Clifford Algebra http://www.av8n.com/physics/clifford-intro.htm Clifford Algebras http://math.ucr.edu/home/baez/octonions/node6.htmlCli ord Algebras, Cli ord Groups, and a Generalization of the Quaternions: The Pin and Spin Groupshttp://www.cis.upenn.edu/~cis610/clifford.pdf AIM math: Representations of E8 http://www.aimath.org/E8/ Dirac belt trick http://gregegan.customer.netspace.net.au/APPLETS/21/21.html Three geometric theorems http://divisbyzero.com/2010/12/24/three-geometric-theorems/ What is E8? http://www.aimath.org/E8/e8.html Three geometric theorems « Division by Zero http://divisbyzero.com/2010/12/24/three-geometric-theorems/ A Geometric Theory Of Everything http://www.science20.com/quantum_diaries_survivor/geometric_theory_everything A Geometric Theory of Everything: Scientific American http://www.scientificamerican.com/article.cfm?id=a-geometric-theory-of-everything A Geometric Theory of Everything « Not Even Wrong http://www.math.columbia.edu/~woit/wordpress/?p=3292 E8 (mathematics) - Wikipedia, the free encyclopedia http://en.wikipedia.org/wiki/E8_(mathematics) Cayley graphs and the geometry of groups « What"s new http://terrytao.wordpress.com/2010/07/10/cayley-graphs-and-the-geometry-of-groups/ On growth and form : Thompson, D'Arcy Wentworth, 1860-1948 http://www.archive.org/details/ongrowthform00thom The Geometry of the MRB constant http://math-blog.com/2010/11/21/the-geometry-of-the-mrb-constant/ La línea de Simson | Gaussianos http://gaussianos.com/la-linea-de-simson/ Pictures of Modular Curves (III) | The n-Category Café http://golem.ph.utexas.edu/category/2010/11/pictures_of_modular_curves_iii.html Reflections and Rotations http://www.youtube.com/watch?v=gJMJBc-f9IQ&feature=related Trigonometric functions and rational multiples of pi http://divisbyzero.com/2010/10/28/trigonometric-functions-and-rational-multiples-of-pi/ Finding Haystacks (and Similar Structures) in Geometry http://valis.cs.uiuc.edu/%7Esariel/papers/10/barriers/barriers.pdf Los centros del triangulo: el punto de Lemoine http://gaussianos.com/los-centros-del-triangulo-el-punto-de-lemoine/ A Geometric Paradox | Futility Closet http://www.futilitycloset.com/2010/09/04/a-geometric-paradox/ Physics intuitions: Alternative Pythagorean quadruples and other extensions to Pythagoras theorem http://commonsensequantum.blogspot.com/2010/08/alternative-pythagorean-quadruples-and.html Physics intuitions: A Pythagorean relation for any triangle? http://commonsensequantum.blogspot.com/2010/08/pythagorean-relation-for-any-triangle.html Los centros del triángulo: el centro de la circunferencia de los nueve puntos | Gaussianos http://gaussianos.com/los-centros-del-triangulo-el-centro-de-la-circunferencia-de-los-nueve-puntos/ Physics intuitions: Lost theorem about angular proportions http://commonsensequantum.blogspot.com/2010/06/lost-theorem-about-angular-proportions.html Variations on dividing circular area into equal parts http://commonsensequantum.blogspot.com/2010/03/variations-on-dividing-circular-area.html Bill Kerr: 40 maths shapes challenges http://billkerr2.blogspot.com/2009/08/40-maths-shapes-challenges.html GeoGebra http://www.geogebra.org/cms/Free mathematics software for learning and teaching Quantum mechanics and geometry http://sbseminar.wordpress.com/2009/11/16/quantum-mechanics-and-geometry/ Rhombus tilings and an over-constrained recurrence http://sbseminar.wordpress.com/2009/10/21/rhombus-tilings-and-an-over-constrained-recurrence/ Historia de la Geometria http://www.euclides.org/menu/articles/historiadelageometria.htm Mis Enlaceshttp://www.delicious.com/ajlopez/geometry Nos leeemos! Angel "Java" Lopezhttp://www.ajlopez.comhttp://twitter.com/ajlopez