Are Q-curves now known to be modular? - MathOverflow most recent 30 from http://mathoverflow.net2013-06-19T21:21:04Zhttp://mathoverflow.net/feeds/question/3927http://www.creativecommons.org/licenses/by-nc/2.5/rdfhttp://mathoverflow.net/questions/3927/are-q-curves-now-known-to-be-modularAre Q-curves now known to be modular?Kevin Buzzard2009-11-03T12:22:40Z2009-11-03T14:07:10Z
<p>I really should know the answer to this, but I don't, so I'll ask here.</p>
<p>A <em>Q-curve</em> is an elliptic curve E over Q-bar which is isogenous to all its Galois conjugates. A Q-curve is <em>modular</em> if it's isogenous (over Q-bar) to some factor of the Jacobian of X_1(N) for some N>=1 (here X_1(N) is the compact modular curve over Q-bar).</p>
<p>Has current machinery proved the well-known conjecture that all Q-curves are modular yet?</p>
<p>Remark: I know there are many partial results. What I'm trying to establish is whether things like Khare-Wintenberger plus best-known modularity lifting theorems are strong enough to give the full conjecture yet, or whether we're still waiting.</p>
http://mathoverflow.net/questions/3927/are-q-curves-now-known-to-be-modular/3936#3936Answer by Lavender Honey for Are Q-curves now known to be modular?Lavender Honey2009-11-03T14:07:10Z2009-11-03T14:07:10Z<p>Yes, this is a consequence of Serre's conjecture. The canonical reference is probably Corollary 6.2 of Ribet's paper on Q-curves:</p>
<p><a href="http://math.berkeley.edu/~ribet/Articles/korea.pdf" rel="nofollow">http://math.berkeley.edu/~ribet/Articles/korea.pdf</a></p>