1.0Istituto Grothendieckhttps://igrothendieck.org/en/Miranda Martinengohttps://igrothendieck.org/en/author/miranda/rich600338<blockquote class="wp-embedded-content" data-secret="2pbQlGtxCu"><a href="https://igrothendieck.org/en/la-poste-celebrates-alexander-grothendieck/">La Poste celebrates Alexander Grothendieck</a></blockquote><iframe sandbox="allow-scripts" security="restricted" src="https://igrothendieck.org/en/la-poste-celebrates-alexander-grothendieck/embed/#?secret=2pbQlGtxCu" width="600" height="338" title="“La Poste celebrates Alexander Grothendieck” — Istituto Grothendieck" data-secret="2pbQlGtxCu" frameborder="0" marginwidth="0" marginheight="0" scrolling="no" class="wp-embedded-content"></iframe><script> /*! This file is auto-generated */ !function(d,l){"use strict";l.querySelector&&d.addEventListener&&"undefined"!=typeof URL&&(d.wp=d.wp||{},d.wp.receiveEmbedMessage||(d.wp.receiveEmbedMessage=function(e){var t=e.data;if((t||t.secret||t.message||t.value)&&!/[^a-zA-Z0-9]/.test(t.secret)){for(var s,r,n,a=l.querySelectorAll('iframe[data-secret="'+t.secret+'"]'),o=l.querySelectorAll('blockquote[data-secret="'+t.secret+'"]'),c=new RegExp("^https?:$","i"),i=0;i<o.length;i++)o[i].style.display="none";for(i=0;i<a.length;i++)s=a[i],e.source===s.contentWindow&&(s.removeAttribute("style"),"height"===t.message?(1e3<(r=parseInt(t.value,10))?r=1e3:~~r<200&&(r=200),s.height=r):"link"===t.message&&(r=new URL(s.getAttribute("src")),n=new URL(t.value),c.test(n.protocol))&&n.host===r.host&&l.activeElement===s&&(d.top.location.href=t.value))}},d.addEventListener("message",d.wp.receiveEmbedMessage,!1),l.addEventListener("DOMContentLoaded",function(){for(var e,t,s=l.querySelectorAll("iframe.wp-embedded-content"),r=0;r<s.length;r++)(t=(e=s[r]).getAttribute("data-secret"))||(t=Math.random().toString(36).substring(2,12),e.src+="#?secret="+t,e.setAttribute("data-secret",t)),e.contentWindow.postMessage({message:"ready",secret:t},"*")},!1)))}(window,document); //# sourceURL=https://igrothendieck.org/wp-includes/js/wp-embed.min.js </script> https://igrothendieck.org/wp-content/uploads/2025/06/20250620_TimbreLaPoste_Grothendieck.webp441600On 16 June 2025, La Poste honoured Alexander Grothendieck by issuing a postage stamp.Prof. Caramello, President of the Institute, had the honour of contributing to the creation of the stamp. In particular, she was involved in choosing the mathematical formula to be reproduced on the stamp.It represents one of the fundamental principles of Grothendieck's work, the method of relativity (which consists of replacing the study of objects with that of morphisms between them), which he introduced in his new foundations for algebraic geometry.Grothendieck used to begin his seminars by writing this expression on the blackboard.