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 145<br />
Remark 6.12.1. By applying Corollary 6.12, a similar remark to Remark 5.6.1<br />
may be made concerning the Θ ± -bridges, Θ ell -bridges, andΘ ±ell -<strong>Hodge</strong> theaters<br />
studied in the present §6. We leave the routine details to the reader.<br />
Remark 6.12.2.<br />
Relative to a fixed collection <strong>of</strong> initial Θ-data:<br />
(i) Suppose that ( † F T → † F ≻ )isaΘ ± -bridge; write( † D T → † D ≻ )for<br />
the associated D-Θ ± -bridge [cf. Definition 6.11, (i)]. Then Proposition 6.7 gives<br />
a functorial algorithm for constructing a D-Θ-bridge ( † D T → † D > )fromthis<br />
D-Θ ± -bridge ( † D T → † D ≻ ). Suppose that this D-Θ-bridge ( † D T<br />
→ † D > )<br />
arises as the D-Θ-bridge associated to a Θ-bridge ( ‡ F J → ‡ F > ‡ HT Θ )[so<br />
J = T — cf. Definition 5.5, (ii)]. Then since the portion “ ‡ F J → ‡ F > ”<strong>of</strong>this<br />
Θ-bridge is completely determined [cf. Definition 5.5, (ii), (d)] by the associated<br />
D-Θ-bridge, one verifies immediately that<br />
one may regard this portion “ ‡ F J → ‡ F > ” <strong>of</strong> the Θ-bridge as having been<br />
constructed via a functorial algorithm similar to the functorial algorithm <strong>of</strong><br />
Proposition 6.7 [cf. also Definition 5.5, (ii), (d); the discussion <strong>of</strong> Remark<br />
5.3.1] from the Θ ± -bridge ( † F T → † F ≻ ).<br />
Since, moreover, isomorphisms between Θ-bridges are in natural bijective correspondence<br />
with isomorphisms between the associated D-Θ-bridges [cf. Corollary<br />
5.6, (ii)], it thus follows immediately [cf. Corollary 5.3, (ii)] that isomorphisms<br />
between Θ-bridges are in natural bijective correspondence with isomorphisms between<br />
the portions <strong>of</strong> Θ-bridges [i.e., “ ‡ F J → ‡ F > ”] considered above. Thus, in<br />
summary, if ( ‡ F J → ‡ F > ‡ HT Θ )isaΘ-bridge for which the portion<br />
“ ‡ F J → ‡ F > ” is obtained via the functorial algorithm discussed above from the<br />
Θ ± -bridge ( † F T → † F ≻ ), then, for simplicity, we shall describe this state <strong>of</strong> affairs<br />
by saying that<br />
the Θ-bridge ( ‡ F J → ‡ F > ‡ HT Θ )isglued to the Θ ± -bridge<br />
( † F T → † F ≻ ) via the functorial algorithm <strong>of</strong> Proposition 6.7.<br />
A similar [but easier!] construction may be given for D-Θ-bridges and D-Θ ± -<br />
bridges. We leave the routine details <strong>of</strong> giving a more explicit description [say, in<br />
the style <strong>of</strong> the statement <strong>of</strong> Proposition 6.7] <strong>of</strong> such functorial algorithms to the<br />
reader.<br />
(ii) Now observe that<br />
by gluing aΘ ±ell -<strong>Hodge</strong> theater [cf. Definition 6.11, (iii)] to a ΘNF-<br />
<strong>Hodge</strong> theater [cf. Definition 5.5, (iii)] along the respective associated<br />
Θ ± -andΘ-bridges via the functorial algorithm <strong>of</strong> Proposition 6.7 [cf. (i)],<br />
one obtains the notion <strong>of</strong> a<br />
“Θ ±ell NF-<strong>Hodge</strong>-theater”<br />
— cf. Definition 6.13, (i), below. Here, we note that by Proposition 4.8, (ii);<br />
Corollary 5.6, (ii), the gluing isomorphism that occurs in such a gluing operation