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AlffRamDivisor
Returns the ramification divisor of a divisor.
Syntax:
A := AlffRamDivisor(D);
A := AlffRamDivisor(F);
alff divisor |
A |
the ramification divisor of D |
alff divisor |
D |
|
alff |
F |
equivalent to taking D = 0 |
See also: AlffWronskian, AlffWronskianOrders, AlffWeierstrassPlaces, AlffGapNumbers, AlffDiff, AlffDifferentiation
Description:
Let F/k be an algebraic function field, x a separating
variable and D a divisor. The ramification divisor
of D is defined to be i(D) ( W - D ) + \bigl(
W_x(D) \bigr) + \nu (dx),
where W is a canonical divisor of F/k, W_x(D) is
the determinant
of the Wronksi matrix of D with respect to x and \nu is the
sum of the Wronski orders of D with respect to x. It is positive
and consists of the D-Weierstra\ss{} places.
The constant field k is required to be exact.
Example:
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