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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118 SHINICHI MOCHIZUKI<br />
[cf. Examples 3.2, (iii); 3.3, (i); 3.4, (i)] <strong>of</strong> the various p-adic and archimedean<br />
Frobenioids [cf. [FrdII], Example 1.1, (ii); [FrdII], Example 3.3, (ii)] that appear<br />
in an F-prime-strip that it makes sense to speak <strong>of</strong> the “pull-back” — i.e., by<br />
forming the “categorical fiber product” [cf. [FrdI], §0; [FrdI], Proposition 1.6] —<br />
<strong>of</strong> the Frobenioids that appear in the F-prime-strip 2 F via the various morphisms<br />
at v ∈ V that constitute φ. That is to say, it follows from our assumptions on<br />
φ [cf. also [AbsTopIII], Proposition 3.2, (iv)] that φ determines a pulled-back F-<br />
prime-strip “φ ∗ ( 2 F)”, whose associated D-prime-strip [cf. Remark 5.2.1, (i)] is<br />
tautologically equal to 1 D. On the other hand, by Corollary 5.3, (ii), it follows<br />
that this tautological equality <strong>of</strong> associated D-prime-strips uniquely determines an<br />
isomorphism 1 F → ∼ φ ∗ ( 2 F). Then we define the arrow ψ : 1 F → 2 F to be the<br />
collection <strong>of</strong> data consisting <strong>of</strong> φ and this isomorphism 1 F → ∼ φ ∗ ( 2 F); we refer to ψ<br />
as the “morphism uniquely determined by φ” or the “uniquely determined morphism<br />
that lies over φ”. Also, we shall apply various terms used to describe a morphism<br />
φ <strong>of</strong> D-prime-strips to the “arrow” <strong>of</strong> F-prime-strips determined by φ.<br />
(ii) The conventions discussed in (i) concerning liftings <strong>of</strong> morphisms <strong>of</strong> D-<br />
prime-strips may also be applied to poly-morphisms. We leave the routine details<br />
to the reader.<br />
Remark 5.3.2. Just as in the case <strong>of</strong> Corollary 5.3, (i), (ii), the rigidity property <strong>of</strong><br />
Corollary 5.3, (iv), may be regarded as being essentially a consequence <strong>of</strong> “Kummerreadiness”<br />
[cf. Remarks 5.1.3, 5.2.2] <strong>of</strong> the tempered Frobenioid F v<br />
— cf. also the<br />
arguments applied in the pro<strong>of</strong>s <strong>of</strong> [AbsTopIII], Proposition 3.2, (iv); [AbsTopIII],<br />
Corollary 5.2, (iv).<br />
Remark 5.3.3. We take this opportunity to rectify a minor oversight in [FrdI].<br />
The hypothesis that the Frobenioids under consideration be <strong>of</strong> “unit-pr<strong>of</strong>inite type”<br />
in [FrdI], Proposition 5.6 — hence also in [FrdI], Corollary 5.7, (iii) — may be<br />
removed. Indeed, if, in the notation <strong>of</strong> the pro<strong>of</strong> <strong>of</strong> [FrdI], Proposition 5.6, one<br />
writes φ ′ p = c p · φ p ,wherec p ∈O × (A), for p ∈ Primes, then one has<br />
c 2 · c 2 p · φ 2 · φ p = c 2 · φ 2 · c p · φ p = φ ′ 2 · φ ′ p = φ ′ p · φ ′ 2<br />
= c p · φ p · c 2 · φ 2 = c p · c p 2 · φ p · φ 2 = c p · c p 2 · φ 2 · φ p<br />
—soc 2 · c 2 p = c p · c p 2 , i.e., c p = c p−1<br />
2 ,forp ∈ Primes. Thus,φ ′ p = c −1<br />
2 · φ p · c 2 ,soby<br />
taking u def<br />
= c −1<br />
2 ,onemayeliminate the final two paragraphs <strong>of</strong> the pro<strong>of</strong> <strong>of</strong> [FrdI],<br />
Proposition 5.6.<br />
Let<br />
† HT Θ =({ † F v<br />
} v∈V , † F ⊩ mod)<br />
be a Θ-<strong>Hodge</strong> theater [relative to the given initial Θ-data] such that the associated<br />
D-prime-strip { † D v } v∈V is [for simplicity] equal to the D-prime-strip † D > <strong>of</strong> the<br />
D-ΘNF-<strong>Hodge</strong> theater in the discussion preceding Example 5.1. Write<br />
† F >