Citation
Sitaraman, Sankar (1994) Arithmetic of cyclotomic fields and Fermat-type equations. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/rkaf-ff17. https://resolver.caltech.edu/CaltechTHESIS:05162013-100413388
Abstract
Let l be any odd prime, and ζ a primitive l-th root of unity. Let C_l be the l-Sylow subgroup of the ideal class group of Q(ζ). The Teichmüller character w : Z_l → Z^*_l is given by w(x) = x (mod l), where w(x) is a p-1-st root of unity, and x ∈ Z_l. Under the action of this character, C_l decomposes as a direct sum of C^((i))_l, where C^((i))_l is the eigenspace corresponding to w^i. Let the order of C^((3))_l be l^h_3). The main result of this thesis is the following: For every n ≥ max( 1, h_3 ), the equation x^(ln) + y^(ln) + z^(ln) = 0 has no integral solutions (x,y,z) with l ≠ xyz. The same result is also proven with n ≥ max(1,h_5), under the assumption that C_l^((5)) is a cyclic group of order l^h_5. Applications of the methods used to prove the above results to the second case of Fermat's last theorem and to a Fermat-like equation in four variables are given.
The proof uses a series of ideas of H.S. Vandiver ([Vl],[V2]) along with a theorem of M. Kurihara [Ku] and some consequences of the proof of lwasawa's main conjecture for cyclotomic fields by B. Mazur and A. Wiles [MW]. In [V1] Vandiver claimed that the first case of Fermat's Last Theorem held for l if l did not divide the class number h^+ of the maximal real subfield of Q(e^(2πi/i)). The crucial gap in Vandiver's attempted proof that has been known to experts is explained, and complete proofs of all the results used from his papers are given.
Item Type: | Thesis (Dissertation (Ph.D.)) |
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Subject Keywords: | Mathematics |
Degree Grantor: | California Institute of Technology |
Division: | Physics, Mathematics and Astronomy |
Major Option: | Mathematics |
Thesis Availability: | Public (worldwide access) |
Research Advisor(s): |
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Thesis Committee: |
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Defense Date: | 24 May 1994 |
Record Number: | CaltechTHESIS:05162013-100413388 |
Persistent URL: | https://resolver.caltech.edu/CaltechTHESIS:05162013-100413388 |
DOI: | 10.7907/rkaf-ff17 |
Default Usage Policy: | No commercial reproduction, distribution, display or performance rights in this work are provided. |
ID Code: | 7715 |
Collection: | CaltechTHESIS |
Deposited By: | Benjamin Perez |
Deposited On: | 16 May 2013 18:36 |
Last Modified: | 09 Nov 2022 19:20 |
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