{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,30]],"date-time":"2025-10-30T12:09:55Z","timestamp":1761826195678,"version":"build-2065373602"},"reference-count":0,"publisher":"European Mathematical Society - EMS - Publishing House GmbH","issue":"2","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Port. Math."],"published-print":{"date-parts":[[2013,8,2]]},"abstract":"<jats:p>\n                    We study natural variations of the\n                    <jats:inline-formula>\n                      <jats:tex-math>\\mathrm{G}_2<\/jats:tex-math>\n                    <\/jats:inline-formula>\n                    structure\n                    <jats:inline-formula>\n                      <jats:tex-math>\\sigma_0\\in\\Lambda^3_+<\/jats:tex-math>\n                    <\/jats:inline-formula>\n                    existing on the unit tangent sphere bundle\n                    <jats:inline-formula>\n                      <jats:tex-math>SM<\/jats:tex-math>\n                    <\/jats:inline-formula>\n                    of any oriented Riemannian 4-manifold\n                    <jats:inline-formula>\n                      <jats:tex-math>M<\/jats:tex-math>\n                    <\/jats:inline-formula>\n                    . We find a circle of structures for which the induced metric is the usual one, the so-called Sasaki metric, and prove how the original structure has a preferred role in the theory. We deduce the equations of calibration and cocalibration, as well as those of\n                    <jats:inline-formula>\n                      <jats:tex-math>W_3<\/jats:tex-math>\n                    <\/jats:inline-formula>\n                    pure type and nearly-parallel type.\n                  <\/jats:p>","DOI":"10.4171\/pm\/1929","type":"journal-article","created":{"date-parts":[[2013,8,2]],"date-time":"2013-08-02T17:45:06Z","timestamp":1375465506000},"page":"145-160","source":"Crossref","is-referenced-by-count":3,"title":["Variations of gwistor space"],"prefix":"10.4171","volume":"70","author":[{"given":"Rui","family":"Albuquerque","sequence":"first","affiliation":[{"name":"Universidade de \u00c9vora, Portugal"}]}],"member":"2673","container-title":["Portugaliae Mathematica"],"original-title":[],"link":[{"URL":"http:\/\/www.ems-ph.org\/fulltext\/10.4171\/PM\/1929","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,30]],"date-time":"2025-10-30T12:05:26Z","timestamp":1761825926000},"score":1,"resource":{"primary":{"URL":"https:\/\/ems.press\/doi\/10.4171\/pm\/1929"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2013,8,2]]},"references-count":0,"journal-issue":{"issue":"2"},"URL":"https:\/\/doi.org\/10.4171\/pm\/1929","relation":{},"ISSN":["0032-5155","1662-2758"],"issn-type":[{"type":"print","value":"0032-5155"},{"type":"electronic","value":"1662-2758"}],"subject":[],"published":{"date-parts":[[2013,8,2]]}}}