{"id":194,"date":"2025-07-18T21:44:50","date_gmt":"2025-07-18T14:44:50","guid":{"rendered":"https:\/\/algebra.math-ugm.id\/?p=194"},"modified":"2025-07-28T10:50:35","modified_gmt":"2025-07-28T03:50:35","slug":"5th-day-cimpa-school-2025-on-arithmetic-in-action-number-theory-and-its-applications-to-cryptography-and-coding-theory","status":"publish","type":"post","link":"https:\/\/algebra.math-ugm.id\/en\/5th-day-cimpa-school-2025-on-arithmetic-in-action-number-theory-and-its-applications-to-cryptography-and-coding-theory\/","title":{"rendered":"5th Day: CIMPA SCHOOL 2025 on Arithmetic in Action: Number Theory and its Applications to Cryptography and Coding Theory"},"content":{"rendered":"<p><\/p>\n<div id=\"header-image\">\n<header class=\"page-header\">\n<div><\/div>\n<\/header>\n<\/div>\n<div class=\"entry-content\">\n<p style=\"text-align: justify;\"><strong><span style=\"font-size: 14pt;\">Universitas Gadjah Mada, Yogyakarta, Indonesia<\/span><\/strong><\/p>\n<p style=\"text-align: justify;\"><strong><span style=\"font-size: 14pt;\">July 18, 2025<\/span><\/strong><\/p>\n<p><span style=\"color: #000000; font-size: 14pt; text-align: justify;\">Lecturing Session<\/span><\/p>\n<div class=\"entry-content\">\n<p style=\"text-align: justify;\">The fifth day of CIMPA SCHOOL 2025 began with a lecture by Dr. Francesco Campagna, who continued his discussion on Elliptic Curves over Finite Fields. He introduced the notion of the boundedness of the number of solutions of elliptic curves and stated the Hasse\u2013Weil Theorem. The lecture then moved on to Frobenius isogeny and the degree of isogenies, followed by a clear proof demonstrating that (E) possesses a ring structure.<\/p>\n<p style=\"text-align: justify;\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-198 size-large\" src=\"https:\/\/algebra.math-ugm.id\/wp-content\/uploads\/2025\/07\/photo_2025-07-18-21.38.08-1024x768.jpeg\" alt=\"\" width=\"640\" height=\"480\" srcset=\"https:\/\/algebra.math-ugm.id\/wp-content\/uploads\/2025\/07\/photo_2025-07-18-21.38.08-1024x768.jpeg 1024w, https:\/\/algebra.math-ugm.id\/wp-content\/uploads\/2025\/07\/photo_2025-07-18-21.38.08-300x225.jpeg 300w, https:\/\/algebra.math-ugm.id\/wp-content\/uploads\/2025\/07\/photo_2025-07-18-21.38.08-768x576.jpeg 768w, https:\/\/algebra.math-ugm.id\/wp-content\/uploads\/2025\/07\/photo_2025-07-18-21.38.08.jpeg 1280w\" sizes=\"auto, (max-width: 640px) 100vw, 640px\" \/><\/p>\n<p style=\"text-align: justify;\">The next lecture was delivered by Prof. Michel Waldschmidt, who began his first lecture on Lattices. He introduced the topology on subgroups of the real numbers and the classification of closed subgroups of \u211d\u207f. Using foundational theory on vector spaces E, he presented two equivalent definitions of lattices within E. The lecture continued with the study of key properties when E = \u211d\u207f, including the concepts of the fundamental domain, covolume, density, and the dual lattice and its relationship with the original lattice. Prof. Waldschmidt concluded the lecture by providing a detailed example on \u211d\u00b2.<img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-195 size-large\" style=\"color: #737373; font-size: 1rem;\" src=\"https:\/\/algebra.math-ugm.id\/wp-content\/uploads\/2025\/07\/photo_2025-07-18-21.38.03-1024x768.jpeg\" alt=\"\" width=\"640\" height=\"480\" srcset=\"https:\/\/algebra.math-ugm.id\/wp-content\/uploads\/2025\/07\/photo_2025-07-18-21.38.03-1024x768.jpeg 1024w, https:\/\/algebra.math-ugm.id\/wp-content\/uploads\/2025\/07\/photo_2025-07-18-21.38.03-300x225.jpeg 300w, https:\/\/algebra.math-ugm.id\/wp-content\/uploads\/2025\/07\/photo_2025-07-18-21.38.03-768x576.jpeg 768w, https:\/\/algebra.math-ugm.id\/wp-content\/uploads\/2025\/07\/photo_2025-07-18-21.38.03.jpeg 1280w\" sizes=\"auto, (max-width: 640px) 100vw, 640px\" \/><\/p>\n<h1 style=\"text-align: justify;\"><span style=\"font-size: 14pt;\">Exercise Session<\/span><\/h1>\n<p style=\"text-align: justify;\">Participants continued their exercises on modular forms in a productive environment, actively interacting with the speaker team for guidance and discussion.<img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-197 size-large\" style=\"color: #737373; font-size: 1rem;\" src=\"https:\/\/algebra.math-ugm.id\/wp-content\/uploads\/2025\/07\/photo_2025-07-18-21.38.06-1024x576.jpeg\" alt=\"\" width=\"640\" height=\"360\" srcset=\"https:\/\/algebra.math-ugm.id\/wp-content\/uploads\/2025\/07\/photo_2025-07-18-21.38.06-1024x576.jpeg 1024w, https:\/\/algebra.math-ugm.id\/wp-content\/uploads\/2025\/07\/photo_2025-07-18-21.38.06-300x169.jpeg 300w, https:\/\/algebra.math-ugm.id\/wp-content\/uploads\/2025\/07\/photo_2025-07-18-21.38.06-768x432.jpeg 768w, https:\/\/algebra.math-ugm.id\/wp-content\/uploads\/2025\/07\/photo_2025-07-18-21.38.06.jpeg 1280w\" sizes=\"auto, (max-width: 640px) 100vw, 640px\" \/><\/p>\n<h1 style=\"text-align: justify;\"><span style=\"font-size: 14pt;\">Extra Activity<\/span><\/h1>\n<p style=\"text-align: justify;\">At the end of the day, there were two short presentations where participants shared their research interests, allowing them to introduce their work and explore possible collaborations with fellow participants.<img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-196 size-large\" style=\"color: #737373; font-size: 1rem;\" src=\"https:\/\/algebra.math-ugm.id\/wp-content\/uploads\/2025\/07\/photo_2025-07-18-21.38.05-1024x768.jpeg\" alt=\"\" width=\"640\" height=\"480\" srcset=\"https:\/\/algebra.math-ugm.id\/wp-content\/uploads\/2025\/07\/photo_2025-07-18-21.38.05-1024x768.jpeg 1024w, https:\/\/algebra.math-ugm.id\/wp-content\/uploads\/2025\/07\/photo_2025-07-18-21.38.05-300x225.jpeg 300w, https:\/\/algebra.math-ugm.id\/wp-content\/uploads\/2025\/07\/photo_2025-07-18-21.38.05-768x576.jpeg 768w, https:\/\/algebra.math-ugm.id\/wp-content\/uploads\/2025\/07\/photo_2025-07-18-21.38.05.jpeg 1280w\" sizes=\"auto, (max-width: 640px) 100vw, 640px\" \/><\/p>\n<\/div>\n<\/div>\n<p><\/p>","protected":false},"excerpt":{"rendered":"<p>Universitas Gadjah Mada, Yogyakarta, Indonesia July 18, 2025 Lecturing Session [&hellip;]<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-194","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/algebra.math-ugm.id\/en\/wp-json\/wp\/v2\/posts\/194","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/algebra.math-ugm.id\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/algebra.math-ugm.id\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/algebra.math-ugm.id\/en\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/algebra.math-ugm.id\/en\/wp-json\/wp\/v2\/comments?post=194"}],"version-history":[{"count":4,"href":"https:\/\/algebra.math-ugm.id\/en\/wp-json\/wp\/v2\/posts\/194\/revisions"}],"predecessor-version":[{"id":253,"href":"https:\/\/algebra.math-ugm.id\/en\/wp-json\/wp\/v2\/posts\/194\/revisions\/253"}],"wp:attachment":[{"href":"https:\/\/algebra.math-ugm.id\/en\/wp-json\/wp\/v2\/media?parent=194"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/algebra.math-ugm.id\/en\/wp-json\/wp\/v2\/categories?post=194"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/algebra.math-ugm.id\/en\/wp-json\/wp\/v2\/tags?post=194"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}