{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,5]],"date-time":"2025-12-05T12:18:14Z","timestamp":1764937094334,"version":"build-2065373602"},"reference-count":0,"publisher":"European Mathematical Society - EMS - Publishing House GmbH","issue":"7","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Rev. Mat. Iberoam."],"published-print":{"date-parts":[[2019,7,22]]},"abstract":"<jats:p>\n                    We discover a fundamental exterior differential system of Riemannian geometry; indeed, an intrinsic and invariant global system of differential forms of degree\n                    <jats:inline-formula>\n                      <jats:tex-math>n<\/jats:tex-math>\n                    <\/jats:inline-formula>\n                    associated to any given oriented Riemannian manifold\n                    <jats:inline-formula>\n                      <jats:tex-math>M<\/jats:tex-math>\n                    <\/jats:inline-formula>\n                    of dimension\n                    <jats:inline-formula>\n                      <jats:tex-math>n + 1<\/jats:tex-math>\n                    <\/jats:inline-formula>\n                    . The framework is that of the tangent sphere bundle of\n                    <jats:inline-formula>\n                      <jats:tex-math>M<\/jats:tex-math>\n                    <\/jats:inline-formula>\n                    . We generalise to a Riemannian setting some results from the theory of hypersurfaces in flat Euclidean space. We give new applications and examples of the associated Euler\u2013Lagrange differential systems.\n                  <\/jats:p>","DOI":"10.4171\/rmi\/1118","type":"journal-article","created":{"date-parts":[[2019,7,22]],"date-time":"2019-07-22T17:30:18Z","timestamp":1563816618000},"page":"2221-2250","source":"Crossref","is-referenced-by-count":4,"title":["A fundamental differential system of Riemannian geometry"],"prefix":"10.4171","volume":"35","author":[{"given":"Rui","family":"Albuquerque","sequence":"first","affiliation":[{"name":"Universidade de \u00c9vora, Portugal"}]}],"member":"2673","container-title":["Revista Matem\u00e1tica Iberoamericana"],"original-title":[],"link":[{"URL":"https:\/\/www.ems-ph.org\/fulltext\/10.4171\/rmi\/1118","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,11,5]],"date-time":"2025-11-05T12:20:33Z","timestamp":1762345233000},"score":1,"resource":{"primary":{"URL":"https:\/\/ems.press\/doi\/10.4171\/rmi\/1118"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,7,22]]},"references-count":0,"journal-issue":{"issue":"7"},"URL":"https:\/\/doi.org\/10.4171\/rmi\/1118","relation":{},"ISSN":["0213-2230","2235-0616"],"issn-type":[{"type":"print","value":"0213-2230"},{"type":"electronic","value":"2235-0616"}],"subject":[],"published":{"date-parts":[[2019,7,22]]}}}