Inter-universal Teichmuller Theory I: Construction of Hodge Theaters
Inter-universal Teichmuller Theory I: Construction of Hodge Theaters
Inter-universal Teichmuller Theory I: Construction of Hodge Theaters
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INTER-UNIVERSAL TEICHMÜLLER THEORY I 19<br />
with a continuous action by an abstract topological group — to the group <strong>of</strong> automorphisms<br />
<strong>of</strong> the topological group G; that is to say, the kernel <strong>of</strong> this surjection<br />
is given by the natural action <strong>of</strong> Ẑ× on O × . In particular, if one works with two<br />
copies G i O ⊲ i ,wherei =0, 1, <strong>of</strong> G O⊲ , which one thinks <strong>of</strong> as being glued<br />
to one another by means <strong>of</strong> an indeterminate isomorphism<br />
(G 0 O × 0 ) ∼<br />
→ (G1 O × 1 )<br />
[i.e., where one thinks <strong>of</strong> each (G i O × i ), for i =0, 1, as an abstract topological<br />
monoid equipped with a continuous action by an abstract topological group], then,<br />
in general, it is a highly nontrivial problem<br />
to describe structures naturally associated to (G 0 O ⊲ 0 )intermsthat<br />
only require the use <strong>of</strong> (G 1 O ⊲ 1 ).<br />
One such structure which is <strong>of</strong> interest in the context <strong>of</strong> the present series <strong>of</strong> papers<br />
[cf., especially, the theory <strong>of</strong> [IUTchII], §1] is the natural cyclotomic rigidity<br />
isomorphism between the group <strong>of</strong> torsion elements <strong>of</strong> O0<br />
⊲ and an analogous<br />
group <strong>of</strong> torsion elements naturally associated to G 0 — i.e., a structure that is<br />
manifestly not preserved by the natural action <strong>of</strong> Ẑ× on O 0 × !<br />
In the context <strong>of</strong> the above discussion <strong>of</strong> Fig. I2.1, it is <strong>of</strong> interest to note the<br />
important role played by Kummer theory in the present series <strong>of</strong> papers [cf. the<br />
Introductions to [IUTchII], [IUTchIII]]. From the point <strong>of</strong> view <strong>of</strong> Fig. I2.1, this<br />
role corresponds to the precise specification <strong>of</strong> the gluing cycle within each twicepunctured<br />
genus one surface in the illustration. Of course, such a precise specification<br />
depends on the twice-punctured genus one surface under consideration, i.e.,<br />
the same gluing cycle is subject to quite different “precise specifications”, relative<br />
to the twice-punctured genus one surface on the left and the twice-punctured genus<br />
one surface on the right. This state <strong>of</strong> affairs corresponds to the quite different<br />
Kummer theories to which the monoids/Frobenioids that appear in the Θ-link are<br />
subject, relative to the Θ ±ell NF-<strong>Hodge</strong> theater in the domain <strong>of</strong> the Θ-link and<br />
the Θ ±ell NF-<strong>Hodge</strong> theater in the codomain <strong>of</strong> the Θ-link. At first glance, it might<br />
appear that the use <strong>of</strong> Kummer theory, i.e., <strong>of</strong> the correspondence determined by<br />
constructing Kummer classes, to achieve this precise specification <strong>of</strong> the relevant<br />
monoids/Frobenioids within each Θ ±ell NF-<strong>Hodge</strong> theater is somewhat arbitrary,<br />
i.e., that one could perhaps use other correspondences [i.e., correspondences not<br />
determined by Kummer classes] to achieve such a precise specification. In fact,<br />
however, the rigidity <strong>of</strong> the relevant local and global monoids equipped with Galois<br />
actions [cf. Corollary 5.3, (i), (ii), (iv)] implies that, if one imposes the natural<br />
condition <strong>of</strong> Galois-compatibility, then<br />
the correspondence furnished by Kummer theory is the only acceptable<br />
choice for constructing the required “precise specification <strong>of</strong> the<br />
relevant monoids/Frobenioids within each Θ ±ell NF-<strong>Hodge</strong> theater”<br />
— cf. also the discussion <strong>of</strong> [IUTchII], Remark 3.6.2, (ii).<br />
The construction <strong>of</strong> the Frobenius-picture described in §I1 is given in the<br />
present paper. More elaborate versions <strong>of</strong> this Frobenius-picture will be discussed