On second case of Strong Fermat's Last Theorem conjecture

Abstract

This article deals with a conjecture, introduced in [GQ] (hereinafter $SFLT2$), which generalizes the second case of Fermat's Last Theorem: {\it Let $p>3$ be a prime. The diophantine equation $\frac{u^p+v^p}{u+v}=w_1^p$ with $u,v,u+v,w_1\in \mathbb{Z}\backslash \{0\}$, $u,v$ coprime and $v\equiv 0\mathrm{mod}p$ has no solution.} Let $\zeta$ be a $p$th primitive root of unity and $K:=\Q(ζ)$. A prime $q$ is said {\it $p$-principal} if the class of any prime ideal ${\mathfrak{q}}_K$ of $K$ over $q$ is a $p$-power of a class. Assume that $SFLT2$ fails for $(p,u,v)$. Let $q$ be any odd prime coprime with $puv$, $f$ the order of $q\mathrm{mod}p$, $n$ the order of $\frac{v}{u}\mathrm{mod}q$, $\xi$ a primitive $n$th root of unity, $\mathfrak{q}$ the prime ideal $(q,u\xi -v)$ of $\Q(ξ)$. In this complement of the article [GQ] revisiting some works of Vandiver, we prove that, if $q$ is {\it $p$-principal} and $n\ne 2p$ then $$(\frac{1+\xi {\zeta }^k}{1+\xi \zeta }{)}^{(q^f-1)/p}\equiv 1\mathrm{mod}\mathfrak{q}fork=1,\dots ,p-1.$$ We shall derive, by example, of this congruence that, for $p$ sufficiently large, a very large number of primes should divide $v$. In an other hand we shall show that if $q$ is any prime of order $f\mathrm{mod}p$ dividing $(u^p+v^p)$ then $$(1-\zeta {)}^{(q^f-1)/p}\equiv p^{-(q^f-1)/p}\mathrm{mod}q,$$ and a result of same nature if $q$ divides $u^p-v^p$, which reinforces strongly the first and second theorem of Furtwängler. The principle of proof relies on the $p$-Hilbert class field theory. Keywords: Fermat's Last Theorem; cyclotomic fields; cyclotomic units; class field theory; Vandiver's and Furtwängler's theorems

Update of version 1, 2013 Apr 23, modifications of Abstract and Main result subsection, replacement of p- power symbols formula by congruences formula in some theorems, new corollaries 2.4 and 2.6. arXiv admin note: substantial text overlap with arXiv:1109.0956

References in corpus (1)

• On Furtwängler's theorems and second case of Fermat's Last Theorem