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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88 SHINICHI MOCHIZUKI<br />
Note that the “desired geometry” in question will also be subject to other requirements.<br />
For instance, in [IUTchIII] [cf. also [IUTchII], §4], we shall make essential<br />
use <strong>of</strong> the global arithmetic — i.e., the ring structure and absolute Galois groups —<br />
<strong>of</strong> number fields. As observed above in Remark 4.3.1, (ii), these global arithmetic<br />
structures are not compatible with the “arithmetic local-analytic sections” constituted<br />
by the prime-strips. In particular, this state <strong>of</strong> affairs imposes the further<br />
requirement that the “geometry” in question be compatible with globalization, i.e.,<br />
that it give rise to the global arithmetic <strong>of</strong> the number fields in question in a fashion<br />
that is independent <strong>of</strong> the various local geometries that appear in the “arithmetic<br />
local-analytic sections” constituted by the prime-strips, but nevertheless admits localization<br />
operations to these various local geometries [cf. Fig. 4.3; the discussion<br />
<strong>of</strong> [IUTchII], Remark 4.11.2, (iii); [AbsTopIII], Remark 3.7.6, (iii), (v)].<br />
local geometry<br />
at v<br />
... local geometry ... local geometry<br />
at v ′ at v ′′<br />
↖ ↑ ↗<br />
global geometry<br />
Fig. 4.3: Globalizability<br />
Finally, in order for the “desired geometry” to be applicable to the theory developed<br />
in the present series <strong>of</strong> papers, it is necessary for it to be based on “étale-like<br />
structures”, soastogiverisetocanonical splittings, asintheétale-picture discussed<br />
in Corollary 3.9, (i). Thus, in summary, the requirements that we wish to impose<br />
on the “desired geometry” are the following:<br />
(a) local independence <strong>of</strong> global structures,<br />
(b) globalizability, in a fashion that is independent <strong>of</strong> local structures,<br />
(c) the property <strong>of</strong> being based on étale-like structures.<br />
Note, in particular, that properties (a), (b) at first glance almost appear to contradict<br />
one another. In particular, the simultaneous realization <strong>of</strong> (a), (b) is highly<br />
nontrivial. For instance, in the case <strong>of</strong> a function field <strong>of</strong> dimension one over a<br />
base field, the simultaneous realization <strong>of</strong> properties (a), (b) appears to require<br />
that one restrict oneself essentially to working with structures that descend to the<br />
base field! It is thus a highly nontrivial consequence <strong>of</strong> the theory <strong>of</strong> [AbsTopIII]<br />
that the mono-anabelian geometry <strong>of</strong> [AbsTopIII] does indeed satisfy all <strong>of</strong> these<br />
requirements (a), (b), (c) [cf. the discussion <strong>of</strong> [AbsTopIII], §I1].<br />
Remark 4.3.3.<br />
(i) One important theme <strong>of</strong> [AbsTopIII] is the analogy between the monoanabelian<br />
theory <strong>of</strong> [AbsTopIII] and the theory <strong>of</strong> Frobenius-invariant indigenous<br />
bundles <strong>of</strong> the sort that appear in p-adic Teichmüller theory [cf. [AbsTopIII],