Lifting and automorphy of reducible mod p Galois representations over global fields
Lifting and automorphy of reducible mod p Galois representations over global fields
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DOI:
10.1007/s00222-021-01085-7
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发表时间:
2020-08
影响因子:
3.1
通讯作者:
N. Fakhruddin;Chandrashekhar B. Khare;Stefan Patrikis
中科院分区:
文献类型:
--
作者:
N. Fakhruddin;Chandrashekhar B. Khare;Stefan Patrikis
We prove the modularity of most reducible, odd representationswithka finite field of characteristic an odd primep. This is an analogue of Serre’s celebrated modularity conjecture (which concerned irreducible, odd representations) for reducible, odd representations. Our proof liftsto an irreducible geometricp-adic representationwhich is known to arise from a newform by results of Skinner–Wiles and Pan. We likewise prove automorphy of many reducible representationswhenFis a global function field of characteristic different fromp, by establishing ap-adic lifting theorem and invoking the work of L. Lafforgue. Crucially, in both cases we show that the actual representation, rather than just its semisimplification, arises from reduction of the geometric representation attached to a cuspidal automorphic representation. Our main theorem establishes a geometric lifting result for modprepresentationsof Galois groups of global fieldsF, valued in reductive groupsG(k), and assumed to be odd whenFis a number field. Thus we find that lifting theorems, combined with automorphy lifting results pioneered by Wiles in the number field case and the results in the global Langlands correspondence proved by Drinfeld and L. Lafforgue in the function field case, give the only known method to access modularity of modpGalois representations both in reducible and irreducible cases.