We provide several extensions of the modular method which were motivated by the problem of completing previous work to prove that, for any integer , the equation
has no non-trivial primitive solutions. In particular, we present four elimination techniques which are based on: (1) establishing reducibility of certain residual Galois representations over a totally real field; (2) generalizing image of inertia arguments to the setting of abelian surfaces; (3) establishing congruences of Hilbert modular forms without the use of often impractical Sturm bounds; and (4) a unit sieve argument which combines information from classical descent and the modular method.
The extensions are of broader applicability and provide further evidence that it is possible to obtain a complete resolution of a family of generalized Fermat equations by remaining within the framework of the modular method. As a further illustration of this, we complete a theorem of Anni–Siksek to show that, for , the only primitive solutions to the equation are trivial.
"SOME EXTENSIONS OF THE MODULAR METHOD AND FERMAT EQUATIONS OF SIGNATURE ." Publ. Mat. 67 (2) 715 - 741, 2023. https://doi.org/10.5565/PUBLMAT6722309