Finally, in passing, we note that this discussion applies, albeit in perhaps a somewhat trivial way, to the isomorphism of Galois groups ΨηX : GK〜→ GK induced by the Frobenius morphism ΦηX in Example 2.6.1, (i): That is to say, from the point of view of classical ring theory, this isomorphism of Galois groups is easily seen to coincide with the identity automorphism of GK. On the other hand, if one takes the point of view that elements of various subquotients of GK are equipped with labels that arise from the isomorphisms ρ or κ of Example 2.6.1, (ii), (iii), i.e., from the reciprocity map of class field theory or Kummer theory, then one must regard such labelling apparatuses as being incompatible with the Frobenius morphism ΦηX . Thus, from this point of view, the isomorphism ΦηX must be regarded as a “mysterious, indeterminate isomorphism” [cf. the discussion of §2.7, (iii)]. (引用終り) 以上
