I fell on the following fact : let p
Let $p$ be an odd prime, let K$K$ denote the p$p$-th cyclotomic field, let L$L$ be an extension of K$K$ with finite degree not divisible by p,$p,$ and assume that the prime ideal $(1 - \zeta)$ of K$K$ (where $\zeta$ denotes a primitive p$p$-th root of unity) ramifies completely in L.$L.$
Let P$P$ denote the only prime ideal of L$L$ dividing $(1 - \zeta)$.
Then in every solution (if any) of the equation $x^p + y^p + z^p = 0$ where x, y$x, y$ and z$z$ are P$P$-integral elements of L$L$ not divisible by P,$P,$ the rational integer t$t$ congruent to x/y $x/y$ (resp. y/z,$y/z,$ resp. z/x$z/x$) modulo P$P$ is a root of the Kummer-Mirimanoff system of congruences $B_{2i}l^{p-2i}(t + \zeta) \equiv 0$ (mod p)$$B_{2i}l^{p-2i}(t + \zeta) \equiv 0\pmod{p}$$ for i = 1$i = 1$ to (p-3)/2$(p-3)/2$, and $l^{p-1}(t + \zeta) \equiv 0 \pmod{p}$, where $l^{j}$ denotes the j$j$-th Kummer logarithmic function (with respect to $\zeta$). Do you know if this was already published ?
Do you know if this was already published ?
Thanks in advance.