Inter-universal Teichmuller Theory I
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・Slightly modified the treatment of Example 3.2 in the discussion of Remark 3.3.2

・Slightly modified the explanation of the torsor structure following the first display
　of Definition 4.1, (ii)

・Slightly modified the wording of Proposition 4.7, (i) ("structure at the" ---> "structure
　at the various")

・Slightly modified the explanation immediately following the second display of Example 5.4, (iv)