On the embedding problem for 2+S4 representations
Let 2+54 denote the double cover of S4 corresponding to the element in H2(54, ℤ/2ℤ) where transpositions lift to elements of order 2 and the product of two disjoint transpositions to elements of order 4. Given an elliptic curve E, let E[2] denote its 2-torsion points. Under some conditions on E elem...
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todo:paper_00255718_v76_n260_p2063_Pacetti2023-10-03T14:36:12Z On the embedding problem for 2+S4 representations Pacetti, A. Galois representations Shimura correspondence Let 2+54 denote the double cover of S4 corresponding to the element in H2(54, ℤ/2ℤ) where transpositions lift to elements of order 2 and the product of two disjoint transpositions to elements of order 4. Given an elliptic curve E, let E[2] denote its 2-torsion points. Under some conditions on E elements in H 1(Galℚ, E[2])\\{0} correspond to Galois extensions N of ℚ with Galois group (isomorphic to) 54. In this work we give an interpretation of the addition law on such fields, and prove that the obstruction for N having a Galois extension Ñ with Gal(Ñ/ℚ) ≃ 2+54 gives a homomorphism s4 +: H1(Galℚ, E[2]) → H 2(Galℚ, ℤ/2ℤ). As a corollary we can prove (if E has conductor divisible by few primes and high rank) the existence of 2-dimensional representations of the absolute Galois group of ℚ attached to E and use them in some examples to construct 3/2 modular forms mapping via the Shimura map to (the modular form of weight 2 attached to) E. © 2007 American Mathematical Society. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00255718_v76_n260_p2063_Pacetti |
institution |
Universidad de Buenos Aires |
institution_str |
I-28 |
repository_str |
R-134 |
collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
topic |
Galois representations Shimura correspondence |
spellingShingle |
Galois representations Shimura correspondence Pacetti, A. On the embedding problem for 2+S4 representations |
topic_facet |
Galois representations Shimura correspondence |
description |
Let 2+54 denote the double cover of S4 corresponding to the element in H2(54, ℤ/2ℤ) where transpositions lift to elements of order 2 and the product of two disjoint transpositions to elements of order 4. Given an elliptic curve E, let E[2] denote its 2-torsion points. Under some conditions on E elements in H 1(Galℚ, E[2])\\{0} correspond to Galois extensions N of ℚ with Galois group (isomorphic to) 54. In this work we give an interpretation of the addition law on such fields, and prove that the obstruction for N having a Galois extension Ñ with Gal(Ñ/ℚ) ≃ 2+54 gives a homomorphism s4 +: H1(Galℚ, E[2]) → H 2(Galℚ, ℤ/2ℤ). As a corollary we can prove (if E has conductor divisible by few primes and high rank) the existence of 2-dimensional representations of the absolute Galois group of ℚ attached to E and use them in some examples to construct 3/2 modular forms mapping via the Shimura map to (the modular form of weight 2 attached to) E. © 2007 American Mathematical Society. |
format |
JOUR |
author |
Pacetti, A. |
author_facet |
Pacetti, A. |
author_sort |
Pacetti, A. |
title |
On the embedding problem for 2+S4 representations |
title_short |
On the embedding problem for 2+S4 representations |
title_full |
On the embedding problem for 2+S4 representations |
title_fullStr |
On the embedding problem for 2+S4 representations |
title_full_unstemmed |
On the embedding problem for 2+S4 representations |
title_sort |
on the embedding problem for 2+s4 representations |
url |
http://hdl.handle.net/20.500.12110/paper_00255718_v76_n260_p2063_Pacetti |
work_keys_str_mv |
AT pacettia ontheembeddingproblemfor2s4representations |
_version_ |
1807314887217512448 |