{"id":1139,"date":"2015-12-11T08:23:28","date_gmt":"2015-12-11T08:23:28","guid":{"rendered":"http:\/\/pageperso.math.univ-toulouse.fr\/hippocampe\/?p=1139"},"modified":"2015-12-16T13:59:12","modified_gmt":"2015-12-16T13:59:12","slug":"lycee-fermat-toulouse-noeuds-et-compagnie","status":"publish","type":"post","link":"https:\/\/perso.math.univ-toulouse.fr\/hippocampe\/2015\/12\/11\/lycee-fermat-toulouse-noeuds-et-compagnie\/","title":{"rendered":"Lyc\u00e9e Fermat (Toulouse) &#8211; Noeuds et compagnie"},"content":{"rendered":"<p style=\"text-align: justify\">Les 30 novembre, 1er et 2 d\u00e9cembre, les \u00e9l\u00e8ves de 1\u00e8re S du lyc\u00e9e Fermat de Toulouse sont venus \u00e0 l&#8217;institut de math\u00e9matiques de l&#8217;universit\u00e9 de Toulouse. Ils \u00e9taient motiv\u00e9s pour s&#8217;attaquer au d\u00e9fi qui les attendait : les noeuds, les tresses et les entrelacs.<\/p>\n<div id=\"attachment_1140\" style=\"width: 310px\" class=\"wp-caption alignleft\"><a href=\"http:\/\/perso.math.univ-toulouse.fr\/hippocampe\/files\/2015\/12\/IMG_3666.jpg\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-1140\" class=\"wp-image-1140 size-medium\" src=\"http:\/\/perso.math.univ-toulouse.fr\/hippocampe\/files\/2015\/12\/IMG_3666-300x225.jpg\" alt=\"Noeud\" width=\"300\" height=\"225\" srcset=\"https:\/\/perso.math.univ-toulouse.fr\/hippocampe\/files\/2015\/12\/IMG_3666-300x225.jpg 300w, https:\/\/perso.math.univ-toulouse.fr\/hippocampe\/files\/2015\/12\/IMG_3666-1024x768.jpg 1024w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><p id=\"caption-attachment-1140\" class=\"wp-caption-text\">Noeud<\/p><\/div>\n<p style=\"text-align: justify\">Un noeud est une ficelle ferm\u00e9e dans l&#8217;espace. On consid\u00e8re que deux noeuds sont les m\u00eames si on peut bouger la ficelle pour passer de l&#8217;un \u00e0 l&#8217;autre. Attention : il est interdit de couper la ficelle et de la recoller. Une question difficile sur les noeuds est de savoir si un noeud se d\u00e9forme en une boucle simple (juste un cercle). On dit alors que le noeud est trivial. \u00c0 votre avis, le noeud sur la photo est-il trivial ?<\/p>\n<p style=\"text-align: justify\">Apr\u00e8s trois jours de r\u00e9flexion, les \u00e9l\u00e8ves du lyc\u00e9e Fermat sont maintenant des sp\u00e9cialistes en herbes des noeuds et des tresses. Ils ont pr\u00e9sent\u00e9 aux membres de l&#8217;institut de math\u00e9matiques des posters sur les sujets suivants :<\/p>\n<ul>\n<li style=\"text-align: justify\">la r\u00e9solution des points doubles,<\/li>\n<li style=\"text-align: justify\">les entrelacs,<\/li>\n<li style=\"text-align: justify\">le coloriage d&#8217;un noeud,<\/li>\n<li style=\"text-align: justify\">les diagrammes de noeud et<\/li>\n<li style=\"text-align: justify\">les tresses.<\/li>\n<\/ul>\n\n\t\t<style>\n\t\t\t#gallery-1 {\n\t\t\t\tmargin: auto;\n\t\t\t}\n\t\t\t#gallery-1 .gallery-item {\n\t\t\t\tfloat: left;\n\t\t\t\tmargin-top: 10px;\n\t\t\t\ttext-align: center;\n\t\t\t\twidth: 33%;\n\t\t\t}\n\t\t\t#gallery-1 img {\n\t\t\t\tborder: 2px solid #cfcfcf;\n\t\t\t}\n\t\t\t#gallery-1 .gallery-caption {\n\t\t\t\tmargin-left: 0;\n\t\t\t}\n\t\t\t\/* see gallery_shortcode() in wp-includes\/media.php *\/\n\t\t<\/style>\n\t\t<div id='gallery-1' class='gallery galleryid-1139 gallery-columns-3 gallery-size-thumbnail'><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon portrait'>\n\t\t\t\t<a href='https:\/\/perso.math.univ-toulouse.fr\/hippocampe\/img_3636\/'><img loading=\"lazy\" decoding=\"async\" width=\"150\" height=\"150\" src=\"https:\/\/perso.math.univ-toulouse.fr\/hippocampe\/files\/2015\/12\/IMG_3636-e1449763157387-150x150.jpg\" class=\"attachment-thumbnail size-thumbnail\" alt=\"\" aria-describedby=\"gallery-1-1111\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-1-1111'>\n\t\t\t\tLes points doubles\n\t\t\t\t<\/dd><\/dl><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/perso.math.univ-toulouse.fr\/hippocampe\/img_3637\/'><img loading=\"lazy\" decoding=\"async\" width=\"150\" height=\"150\" src=\"https:\/\/perso.math.univ-toulouse.fr\/hippocampe\/files\/2015\/12\/IMG_3637-150x150.jpg\" class=\"attachment-thumbnail size-thumbnail\" alt=\"\" aria-describedby=\"gallery-1-1112\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-1-1112'>\n\t\t\t\tLes points doubles\n\t\t\t\t<\/dd><\/dl><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon portrait'>\n\t\t\t\t<a href='https:\/\/perso.math.univ-toulouse.fr\/hippocampe\/img_3638\/'><img loading=\"lazy\" decoding=\"async\" width=\"150\" height=\"150\" src=\"https:\/\/perso.math.univ-toulouse.fr\/hippocampe\/files\/2015\/12\/IMG_3638-e1449763179773-150x150.jpg\" class=\"attachment-thumbnail size-thumbnail\" alt=\"\" aria-describedby=\"gallery-1-1113\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-1-1113'>\n\t\t\t\tLes entrelacs\n\t\t\t\t<\/dd><\/dl><br style=\"clear: both\" \/><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/perso.math.univ-toulouse.fr\/hippocampe\/img_3639\/'><img loading=\"lazy\" decoding=\"async\" width=\"150\" height=\"150\" src=\"https:\/\/perso.math.univ-toulouse.fr\/hippocampe\/files\/2015\/12\/IMG_3639-150x150.jpg\" class=\"attachment-thumbnail size-thumbnail\" alt=\"\" aria-describedby=\"gallery-1-1114\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-1-1114'>\n\t\t\t\tColoriage d&#8217;un noeud\n\t\t\t\t<\/dd><\/dl><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon portrait'>\n\t\t\t\t<a href='https:\/\/perso.math.univ-toulouse.fr\/hippocampe\/img_3640\/'><img loading=\"lazy\" decoding=\"async\" width=\"150\" height=\"150\" src=\"https:\/\/perso.math.univ-toulouse.fr\/hippocampe\/files\/2015\/12\/IMG_3640-e1449763199500-150x150.jpg\" class=\"attachment-thumbnail size-thumbnail\" alt=\"\" aria-describedby=\"gallery-1-1115\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-1-1115'>\n\t\t\t\tColoriage d&#8217;un noeud\n\t\t\t\t<\/dd><\/dl><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon portrait'>\n\t\t\t\t<a href='https:\/\/perso.math.univ-toulouse.fr\/hippocampe\/img_3641\/'><img loading=\"lazy\" decoding=\"async\" width=\"150\" height=\"150\" src=\"https:\/\/perso.math.univ-toulouse.fr\/hippocampe\/files\/2015\/12\/IMG_3641-e1449763212164-150x150.jpg\" class=\"attachment-thumbnail size-thumbnail\" alt=\"\" aria-describedby=\"gallery-1-1116\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-1-1116'>\n\t\t\t\tDiagramme de noeud\n\t\t\t\t<\/dd><\/dl><br style=\"clear: both\" \/><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/perso.math.univ-toulouse.fr\/hippocampe\/img_3642\/'><img loading=\"lazy\" decoding=\"async\" width=\"150\" height=\"150\" src=\"https:\/\/perso.math.univ-toulouse.fr\/hippocampe\/files\/2015\/12\/IMG_3642-150x150.jpg\" class=\"attachment-thumbnail size-thumbnail\" alt=\"\" aria-describedby=\"gallery-1-1117\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-1-1117'>\n\t\t\t\tColoriage d&#8217;un noeud\n\t\t\t\t<\/dd><\/dl><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/perso.math.univ-toulouse.fr\/hippocampe\/img_3643\/'><img loading=\"lazy\" decoding=\"async\" width=\"150\" height=\"150\" src=\"https:\/\/perso.math.univ-toulouse.fr\/hippocampe\/files\/2015\/12\/IMG_3643-150x150.jpg\" class=\"attachment-thumbnail size-thumbnail\" alt=\"\" aria-describedby=\"gallery-1-1118\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-1-1118'>\n\t\t\t\tColoriage d&#8217;un noeud\n\t\t\t\t<\/dd><\/dl><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/perso.math.univ-toulouse.fr\/hippocampe\/img_3644\/'><img loading=\"lazy\" decoding=\"async\" width=\"150\" height=\"150\" src=\"https:\/\/perso.math.univ-toulouse.fr\/hippocampe\/files\/2015\/12\/IMG_3644-150x150.jpg\" class=\"attachment-thumbnail size-thumbnail\" alt=\"\" aria-describedby=\"gallery-1-1119\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-1-1119'>\n\t\t\t\tColoriage d&#8217;un noeud\n\t\t\t\t<\/dd><\/dl><br style=\"clear: both\" \/><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon portrait'>\n\t\t\t\t<a href='https:\/\/perso.math.univ-toulouse.fr\/hippocampe\/img_3645\/'><img loading=\"lazy\" decoding=\"async\" width=\"150\" height=\"150\" src=\"https:\/\/perso.math.univ-toulouse.fr\/hippocampe\/files\/2015\/12\/IMG_3645-e1449763228211-150x150.jpg\" class=\"attachment-thumbnail size-thumbnail\" alt=\"\" aria-describedby=\"gallery-1-1120\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-1-1120'>\n\t\t\t\tLes tresses\n\t\t\t\t<\/dd><\/dl><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon portrait'>\n\t\t\t\t<a href='https:\/\/perso.math.univ-toulouse.fr\/hippocampe\/img_3647\/'><img loading=\"lazy\" decoding=\"async\" width=\"150\" height=\"150\" src=\"https:\/\/perso.math.univ-toulouse.fr\/hippocampe\/files\/2015\/12\/IMG_3647-e1449763241544-150x150.jpg\" class=\"attachment-thumbnail size-thumbnail\" alt=\"\" aria-describedby=\"gallery-1-1121\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-1-1121'>\n\t\t\t\tLes entrelacs\n\t\t\t\t<\/dd><\/dl><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon portrait'>\n\t\t\t\t<a href='https:\/\/perso.math.univ-toulouse.fr\/hippocampe\/img_3648\/'><img loading=\"lazy\" decoding=\"async\" width=\"150\" height=\"150\" src=\"https:\/\/perso.math.univ-toulouse.fr\/hippocampe\/files\/2015\/12\/IMG_3648-e1449763253868-150x150.jpg\" class=\"attachment-thumbnail size-thumbnail\" alt=\"\" aria-describedby=\"gallery-1-1122\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-1-1122'>\n\t\t\t\tLes points doubles\n\t\t\t\t<\/dd><\/dl><br style=\"clear: both\" \/>\n\t\t<\/div>\n\n<p style=\"text-align: justify\">Certains \u00e9l\u00e8ves se sont pos\u00e9s la question de fabriquer un entrelacs (un ensemble de noeuds entrelac\u00e9s) v\u00e9rifiant la propri\u00e9t\u00e9 suivante : tous les noeuds sont accroch\u00e9s, mais si l&#8217;on retire un des noeuds (n&#8217;importe lequel), alors tous les noeuds se retrouvent d\u00e9tach\u00e9s. Un tel exemple d&#8217;entrelacs (avec trois fils) est donn\u00e9 par les <a href=\"https:\/\/fr.wikipedia.org\/wiki\/Anneaux_borrom\u00e9ens\">anneaux Borrom\u00e9ens<\/a>. La famille italienne, les Borromeo, utilisait ces anneaux pour symboliser leur force lorsqu&#8217;ils \u00e9taient unis. Saurez-vous relier ces anneaux au probl\u00e8me suivant ? La professeure de math\u00e9matiques des \u00e9l\u00e8ves de premi\u00e8re S du lyc\u00e9e Fermat souhaite attacher tous ses \u00e9l\u00e8ves \u00a0\u00e0 des barreaux avec une grande chaine, de fa\u00e7on \u00e0 ce qu&#8217;ils ne puissent pas partir en vacances avant la fin des cours. La chaine est accroch\u00e9e \u00e0 tous les \u00e9l\u00e8ves, elle est ensuite entour\u00e9e autour des\u00a0diff\u00e9rents barreaux et attach\u00e9e \u00e0 nouveau aux \u00e9l\u00e8ves. La professeure de math\u00e9matiques d\u00e9cide de donner une chance aux \u00e9l\u00e8ves, elle va scier\u00a0un barreau (c&#8217;est elle\u00a0qui choisit le barreau et non les \u00e9l\u00e8ves). Les \u00e9l\u00e8ves enroulent eux-m\u00eame la chaine autour des diff\u00e9rents barreaux, pouvez-vous les aider \u00e0 \u00eatre lib\u00e9r\u00e9s lorsque la professeure sciera un barreau (bien s\u00fbr, il faut que la chaine soit au moins attach\u00e9e \u00e0 un barreau, sinon la professeure d\u00e9cidera d&#8217;attacher elle-m\u00eame les \u00e9l\u00e8ves) ? Le jeu en vaut la chandelle : s&#8217;ils sont libres, les \u00e9l\u00e8ves partiront en vacances un jour plus t\u00f4t !<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Les 30 novembre, 1er et 2 d\u00e9cembre, les \u00e9l\u00e8ves de 1\u00e8re S du lyc\u00e9e Fermat de Toulouse sont venus \u00e0 l&#8217;institut de math\u00e9matiques de l&#8217;universit\u00e9 de Toulouse. Ils \u00e9taient motiv\u00e9s pour s&#8217;attaquer au d\u00e9fi qui les attendait : les noeuds, les tresses et les entrelacs. Un noeud est une ficelle ferm\u00e9e dans l&#8217;espace. On consid\u00e8re [&hellip;]<\/p>\n","protected":false},"author":131,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[8],"tags":[],"class_list":["post-1139","post","type-post","status-publish","format-standard","hentry","category-stages"],"_links":{"self":[{"href":"https:\/\/perso.math.univ-toulouse.fr\/hippocampe\/wp-json\/wp\/v2\/posts\/1139","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/perso.math.univ-toulouse.fr\/hippocampe\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/perso.math.univ-toulouse.fr\/hippocampe\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/perso.math.univ-toulouse.fr\/hippocampe\/wp-json\/wp\/v2\/users\/131"}],"replies":[{"embeddable":true,"href":"https:\/\/perso.math.univ-toulouse.fr\/hippocampe\/wp-json\/wp\/v2\/comments?post=1139"}],"version-history":[{"count":9,"href":"https:\/\/perso.math.univ-toulouse.fr\/hippocampe\/wp-json\/wp\/v2\/posts\/1139\/revisions"}],"predecessor-version":[{"id":1163,"href":"https:\/\/perso.math.univ-toulouse.fr\/hippocampe\/wp-json\/wp\/v2\/posts\/1139\/revisions\/1163"}],"wp:attachment":[{"href":"https:\/\/perso.math.univ-toulouse.fr\/hippocampe\/wp-json\/wp\/v2\/media?parent=1139"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/perso.math.univ-toulouse.fr\/hippocampe\/wp-json\/wp\/v2\/categories?post=1139"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/perso.math.univ-toulouse.fr\/hippocampe\/wp-json\/wp\/v2\/tags?post=1139"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}