{"version":"1.0","provider_name":"Matem\u00e1ticas y sus fronteras","provider_url":"https:\/\/www.madrimasd.org\/blogs\/matematicas","author_name":"Matem\u00e1ticas y sus fronteras","author_url":"https:\/\/www.madrimasd.org\/blogs\/matematicas\/author\/matematicas","title":"Clasificando nudos - Matem\u00e1ticas y sus fronteras","type":"rich","width":600,"height":338,"html":"<blockquote class=\"wp-embedded-content\" data-secret=\"D1J5p4ZUH0\"><a href=\"https:\/\/www.madrimasd.org\/blogs\/matematicas\/2018\/11\/02\/145874\">Clasificando nudos<\/a><\/blockquote><iframe sandbox=\"allow-scripts\" security=\"restricted\" src=\"https:\/\/www.madrimasd.org\/blogs\/matematicas\/2018\/11\/02\/145874\/embed#?secret=D1J5p4ZUH0\" width=\"600\" height=\"338\" title=\"\u00abClasificando nudos\u00bb \u2014 Matem\u00e1ticas y sus fronteras\" data-secret=\"D1J5p4ZUH0\" frameborder=\"0\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"no\" class=\"wp-embedded-content\"><\/iframe><script>\n\/**\n * WordPress inline HTML embed\n *\n * @since 4.4.0\n * @output wp-includes\/js\/wp-embed.js\n *\n * This file cannot have ampersands in it. This is to ensure\n * it can be embedded in older versions of WordPress.\n * See https:\/\/core.trac.wordpress.org\/changeset\/35708.\n *\/\n(function ( window, document ) {\n\t'use strict';\n\n\tvar supportedBrowser = false,\n\t\tloaded = false;\n\n\t\tif ( document.querySelector ) {\n\t\t\tif ( window.addEventListener ) {\n\t\t\t\tsupportedBrowser = true;\n\t\t\t}\n\t\t}\n\n\t\/** @namespace wp *\/\n\twindow.wp = window.wp || {};\n\n\tif ( !! window.wp.receiveEmbedMessage ) {\n\t\treturn;\n\t}\n\n\t\/**\n\t * Receive embed message.\n\t *\n\t * @param {MessageEvent} e\n\t *\/\n\twindow.wp.receiveEmbedMessage = function( e ) {\n\t\tvar data = e.data;\n\n\t\tif ( ! data ) {\n\t\t\treturn;\n\t\t}\n\n\t\tif ( ! ( data.secret || data.message || data.value ) ) {\n\t\t\treturn;\n\t\t}\n\n\t\tif ( \/[^a-zA-Z0-9]\/.test( data.secret ) ) {\n\t\t\treturn;\n\t\t}\n\n\t\tvar iframes = document.querySelectorAll( 'iframe[data-secret=\"' + data.secret + '\"]' ),\n\t\t\tblockquotes = document.querySelectorAll( 'blockquote[data-secret=\"' + data.secret + '\"]' ),\n\t\t\tallowedProtocols = new RegExp( '^https?:$', 'i' ),\n\t\t\ti, source, height, sourceURL, targetURL;\n\n\t\tfor ( i = 0; i < blockquotes.length; i++ ) {\n\t\t\tblockquotes[ i ].style.display = 'none';\n\t\t}\n\n\t\tfor ( i = 0; i < iframes.length; i++ ) {\n\t\t\tsource = iframes[ i ];\n\n\t\t\tif ( e.source !== source.contentWindow ) {\n\t\t\t\tcontinue;\n\t\t\t}\n\n\t\t\tsource.removeAttribute( 'style' );\n\n\t\t\t\/* Resize the iframe on request. *\/\n\t\t\tif ( 'height' === data.message ) {\n\t\t\t\theight = parseInt( data.value, 10 );\n\t\t\t\tif ( height > 1000 ) {\n\t\t\t\t\theight = 1000;\n\t\t\t\t} else if ( ~~height < 200 ) {\n\t\t\t\t\theight = 200;\n\t\t\t\t}\n\n\t\t\t\tsource.height = height;\n\t\t\t}\n\n\t\t\t\/* Link to a specific URL on request. *\/\n\t\t\tif ( 'link' === data.message ) {\n\t\t\t\tsourceURL = document.createElement( 'a' );\n\t\t\t\ttargetURL = document.createElement( 'a' );\n\n\t\t\t\tsourceURL.href = source.getAttribute( 'src' );\n\t\t\t\ttargetURL.href = data.value;\n\n\t\t\t\t\/* Only follow link if the protocol is in the allow list. *\/\n\t\t\t\tif ( ! allowedProtocols.test( targetURL.protocol ) ) {\n\t\t\t\t\tcontinue;\n\t\t\t\t}\n\n\t\t\t\t\/* Only continue if link hostname matches iframe's hostname. *\/\n\t\t\t\tif ( targetURL.host === sourceURL.host ) {\n\t\t\t\t\tif ( document.activeElement === source ) {\n\t\t\t\t\t\twindow.top.location.href = data.value;\n\t\t\t\t\t}\n\t\t\t\t}\n\t\t\t}\n\t\t}\n\t};\n\n\tfunction onLoad() {\n\t\tif ( loaded ) {\n\t\t\treturn;\n\t\t}\n\n\t\tloaded = true;\n\n\t\tvar isIE10 = -1 !== navigator.appVersion.indexOf( 'MSIE 10' ),\n\t\t\tisIE11 = !!navigator.userAgent.match( \/Trident.*rv:11\\.\/ ),\n\t\t\tiframes = document.querySelectorAll( 'iframe.wp-embedded-content' ),\n\t\t\tiframeClone, i, source, secret;\n\n\t\tfor ( i = 0; i < iframes.length; i++ ) {\n\t\t\t\/** @var {IframeElement} *\/\n\t\t\tsource = iframes[ i ];\n\n\t\t\tsecret = source.getAttribute( 'data-secret' );\n\t\t\tif ( ! secret ) {\n\t\t\t\t\/* Add secret to iframe *\/\n\t\t\t\tsecret = Math.random().toString( 36 ).substr( 2, 10 );\n\t\t\t\tsource.src += '#?secret=' + secret;\n\t\t\t\tsource.setAttribute( 'data-secret', secret );\n\t\t\t}\n\n\t\t\t\/* Remove security attribute from iframes in IE10 and IE11. *\/\n\t\t\tif ( ( isIE10 || isIE11 ) ) {\n\t\t\t\tiframeClone = source.cloneNode( true );\n\t\t\t\tiframeClone.removeAttribute( 'security' );\n\t\t\t\tsource.parentNode.replaceChild( iframeClone, source );\n\t\t\t}\n\n\t\t\t\/*\n\t\t\t * Let post embed window know that the parent is ready for receiving the height message, in case the iframe\n\t\t\t * loaded before wp-embed.js was loaded. When the ready message is received by the post embed window, the\n\t\t\t * window will then (re-)send the height message right away.\n\t\t\t *\/\n\t\t\tsource.contentWindow.postMessage( {\n\t\t\t\tmessage: 'ready',\n\t\t\t\tsecret: secret\n\t\t\t}, '*' );\n\t\t}\n\t}\n\n\tif ( supportedBrowser ) {\n\t\twindow.addEventListener( 'message', window.wp.receiveEmbedMessage, false );\n\t\tdocument.addEventListener( 'DOMContentLoaded', onLoad, false );\n\t\twindow.addEventListener( 'load', onLoad, false );\n\t}\n})( window, document );\n<\/script>\n","description":"Seguimos hablando de nudos en Matem\u00e1ticas y sus fronteras. Dec\u00edamos en la entrada anterior que el inter\u00e9s por los nudos decay\u00f3 al probarse que las teor\u00edas que trataban de explicar con ellos el mundo at\u00f3mico no se sustentaban a tenor de los nuevos descubrimientos sobre la inexistencia del \u00e9ter y la aparici\u00f3n de la mec\u00e1nica cu\u00e1ntica. Pero los matem\u00e1ticos s\u00ed segu\u00edan interesados en el tema. Los top\u00f3logos se sintieron fascinados por estos objetos matem\u00e1ticos. Y una de las cuestiones claves es la de su clasificaci\u00f3n, es decir, \u00bfcu\u00e1ndo podemos decir que dos nudos son equivalentes? Por ejemplo, los dos nudos\u2026","thumbnail_url":"http:\/\/www.madrimasd.org\/blogs\/matematicas\/files\/2018\/11\/monster.gif"}