Stein and Watkins conjectured that for a certain family of elliptic curves E, the X₀(N)-optimal curve and the X₁(N)-optimal curve of the isogeny class 𝓒 containing E of conductor N differ by a 3-isogeny. In this paper, we show that this conjecture is true.
@article{bwmeta1.element.bwnjournal-article-doi-10_4064-aa158-3-2, author = {Dongho Byeon and Donggeon Yhee}, title = {Optimal curves differing by a 3-isogeny}, journal = {Acta Arithmetica}, volume = {161}, year = {2013}, pages = {219-227}, zbl = {1294.11087}, language = {en}, url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-aa158-3-2} }
Dongho Byeon; Donggeon Yhee. Optimal curves differing by a 3-isogeny. Acta Arithmetica, Tome 161 (2013) pp. 219-227. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-aa158-3-2/