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Use Q_4 instead of T_4

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T_4 is nicer because it sounds like "torsion", but T is also used as a variable in ext. coordinates, so Q is better overall since it avoids conflicts later.
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Henry de Valence 2018-04-04 18:26:56 -07:00
parent 34a6de83e0
commit 5385399854
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docs/ristretto-notes.md
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@ -123,10 +123,10 @@ Notice that if \\(xy \neq 0 \\), then exactly two of these points have
\\( (0,-1) \\). This means that we can select a representative modulo
\\(\mathcal E[2]\\) by requiring \\(xy\\) nonnegative and \\(y \neq
0\\), and we can ensure that this condition holds by conditionally
adding a \\(4\\)-torsion point \\(T_4\\) if \\(xy\\) is negative or
adding a \\(4\\)-torsion point \\(Q_4\\) if \\(xy\\) is negative or
\\(y = 0\\).
Convenient choices for \\( T_4 \\) are \\((1,0)\\) when
Convenient choices for \\( Q_4 \\) are \\((1,0)\\) when
\\( a = 1 \\) and \\( (i, 0) \\) when \\( a = -1 \\).
This procedure gives a canonical lift from \\(\mathcal E / \mathcal