196 lines
6.4 KiB
Python
196 lines
6.4 KiB
Python
class as_function:
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def __init__(self, C, g):
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self.curve = C
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F = C.base_ring
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n = C.height
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RxyzQ, Rxyz, x, y, z = C.fct_field
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self.function = RxyzQ(g)
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#self.function = as_reduction(AS, RxyzQ(g))
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def __repr__(self):
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return str(self.function)
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def __eq__(self, other):
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AS = self.curve
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RxyzQ, Rxyz, x, y, z = AS.fct_field
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aux = self - other
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aux = RxyzQ(aux.function)
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aux = aux.numerator()
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aux = as_function(AS, aux)
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aux = aux.expansion_at_infty()
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F = AS.base_ring
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Rt.<t> = LaurentSeriesRing(F, default_prec=AS.prec)
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if Rt(aux).valuation() >= 1:
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return True
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return False
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def __add__(self, other):
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C = self.curve
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g1 = self.function
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g2 = other.function
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return as_function(C, g1 + g2)
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def __sub__(self, other):
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C = self.curve
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g1 = self.function
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g2 = other.function
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return as_function(C, g1 - g2)
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def __rmul__(self, constant):
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C = self.curve
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g = self.function
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return as_function(C, constant*g)
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def __neg__(self):
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C = self.curve
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g = self.function
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return as_function(C, -g)
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def __mul__(self, other):
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if isinstance(other, as_function):
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C = self.curve
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g1 = self.function
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g2 = other.function
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return as_function(C, g1*g2)
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if isinstance(other, as_form):
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C = self.curve
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g1 = self.function
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g2 = other.form
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return as_form(C, g1*g2)
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def __truediv__(self, other):
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C = self.curve
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g1 = self.function
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g2 = other.function
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return as_function(C, g1/g2)
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def __pow__(self, exponent):
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C = self.curve
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g1 = self.function
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return as_function(C, g1^(exponent))
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def expansion_at_infty(self, place = 0):
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C = self.curve
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delta = C.nb_of_pts_at_infty
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F = C.base_ring
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x_series = C.x_series[place]
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y_series = C.y_series[place]
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z_series = C.z_series[place]
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n = C.height
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RxyzQ, Rxyz, x, y, z = C.fct_field
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prec = C.prec
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Rt.<t> = LaurentSeriesRing(F, default_prec=prec)
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g = self.function
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g = RxyzQ(g)
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sub_list = {x : x_series, y : y_series} | {z[j] : z_series[j] for j in range(n)}
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return g.substitute(sub_list)
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def expansion(self, pt = 0):
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C = self.curve
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delta = C.nb_of_pts_at_infty
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F = C.base_ring
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x_series = C.x_series[pt]
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y_series = C.y_series[pt]
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z_series = C.z_series[pt]
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n = C.height
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RxyzQ, Rxyz, x, y, z = C.fct_field
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prec = C.prec
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Rt.<t> = LaurentSeriesRing(F, default_prec=prec)
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g = self.function
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g = RxyzQ(g)
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sub_list = {x : x_series, y : y_series} | {z[j] : z_series[j] for j in range(n)}
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return g.substitute(sub_list)
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def group_action(self, elt):
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C = self.curve
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RxyzQ, Rxyz, x, y, z = C.fct_field
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Rzf, zgen, fgen = C.cover_template.fct_field
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if isinstance(elt, group_elt):
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elt = elt.as_tuple
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AS = self.curve
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n = AS.height
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G = AS.group
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if elt in G.gens:
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ind = G.gens.index(elt)
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gp_action_list = C.cover_template.gp_action[ind]
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sub_list_gen = {zgen[i] : RxyzQ(z[i]) for i in range(n)}|{fgen[i] : RxyzQ(AS.functions[i].function) for i in range(n)}
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sub_list = {x : RxyzQ(x), y : RxyzQ(y)} | {z[j] : RxyzQ(gp_action_list[j].subs(sub_list_gen)) for j in range(n)}
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g = self.function
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return as_function(C, g.substitute(sub_list))
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result = self
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for i in range(len(G.gens)):
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if isinstance(elt, list) or isinstance(elt, tuple): #elt can be a tuple...
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range_limit = elt[i]
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else: # ... or an integer.
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range_limit = elt
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for j in range(range_limit):
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result = result.group_action(G.gens[i])
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return result
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def reduce(self):
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aux = as_reduction(self.curve, self.function)
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return as_function(self.curve, aux)
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def trace(self, super=True, subgp = 0):
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C = self.curve
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C_super = C.quotient
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n = C.height
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F = C.base_ring
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if isinstance(subgp, Integer) or isinstance(subgp, int):
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subgp = C.group.elts
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else:
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super = False
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RxyzQ, Rxyz, x, y, z = C.fct_field
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result = as_function(C, 0)
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for a in subgp:
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result += self.group_action(a)
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result = result.function
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Rxy.<x, y> = PolynomialRing(F, 2)
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Qxy = FractionField(Rxy)
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result = as_reduction(C, result)
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if super:
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return superelliptic_function(C_super, Qxy(result))
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RxyzQ, Rxyz, x, y, z = C.fct_field
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return as_function(C, RxyzQ(result))
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def coordinates(self, prec = 100, basis = 0):
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"Return coordinates in H^1(X, OX)."
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AS = self.curve
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if basis == 0:
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basis = [AS.holomorphic_differentials_basis(), AS.cohomology_of_structure_sheaf_basis()]
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holo_diffs = basis[0]
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coh_basis = basis[1]
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f_products = []
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for f in coh_basis:
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f_products += [[omega.serre_duality_pairing(f) for omega in holo_diffs]]
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product_of_fct_and_omegas = []
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product_of_fct_and_omegas = [omega.serre_duality_pairing(self) for omega in holo_diffs]
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V = (F^(AS.genus())).span_of_basis([vector(a) for a in f_products])
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coh_coordinates = V.coordinates(product_of_fct_and_omegas)
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return coh_coordinates
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def diffn(self):
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C = self.curve
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C_super = C.quotient
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n = C.height
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RxyzQ, Rxyz, x, y, z = C.fct_field
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f = self.function
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y_super = superelliptic_function(C_super, y)
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dy_super = y_super.diffn().form
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dz = C.dz
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result = f.derivative(x)
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result += f.derivative(y)*dy_super
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for i in range(n):
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result += f.derivative(z[i])*dz[i]
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return as_form(C, result)
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def valuation(self, place = 0):
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'''Return valuation at i-th place at infinity.'''
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C = self.curve
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F = C.base_ring
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Rt.<t> = LaurentSeriesRing(F)
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return Rt(self.expansion_at_infty(place = place)).valuation()
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