The subconvexity problem for GL2
Publications Mathématiques de l'IHÉS, Volume 111  (2010), p. 171-271

Generalizing and unifying prior results, we solve the subconvexity problem for the L-functions of GL 1 and GL 2 automorphic representations over a fixed number field, uniformly in all aspects. A novel feature of the present method is the softness of our arguments; this is largely due to a consistent use of canonically normalized period relations, such as those supplied by the work of Waldspurger and Ichino–Ikeda.

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     author = {Michel, Philippe and Venkatesh, Akshay},
     title = {The subconvexity problem for GL2},
     journal = {Publications Math\'ematiques de l'IH\'ES},
     publisher = {Springer-Verlag},
     volume = {111},
     year = {2010},
     pages = {171-271},
     doi = {10.1007/s10240-010-0025-8},
     mrnumber = {2653249},
     language = {en},
     url = {http://www.numdam.org/item/PMIHES_2010__111__171_0}
}
Michel, Philippe; Venkatesh, Akshay. The subconvexity problem for GL2. Publications Mathématiques de l'IHÉS, Volume 111 (2010) , pp. 171-271. doi : 10.1007/s10240-010-0025-8. http://www.numdam.org/item/PMIHES_2010__111__171_0/

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