7. Exact strength: how the named theorems differ from the textbook
- Mazur. Proved: irreducibility of for Frey curves. Not proved: Mazur's theorems on rational isogenies or rational torsion for general curves. For the argument is Kummer or descent, not modular curves.
- Langlands–Tunnell. Proved: the octahedral case with explicit lift, for surjective with cyclotomic determinant, delivered as a weight-one form and then as weight-2 residual modularity with level conditions. Not proved: automorphy of general odd two-dimensional representations with soluble image.
- Modularity lifting. Proved: the two level-conditioned statements of §4.2 for semistable at and . Not proved: a statement without the conditions on , for non-semistable curves, or for other .
- Wiles. Proved: every semistable integral Weierstrass model with is modular in the -matching sense. The hypothesis is on a chosen integral equation; nothing is said about non-semistable curves, modular parametrisations or -functions.
- Ribet. Proved: level lowering for the Frey representation at conductor-supported squarefree levels, in the congruence-of-traces formulation. Not proved: Ribet's theorem for a general modular mod- representation.
- "Irreducible" is -irreducibility of ; absolute irreducibility, where lifting needs it, is derived
inside (
ResidualGaloisRep.isAbsolutelyIrreducible_of_isIrreducible_of_isOdd).