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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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