Changeset 7443:10ffb2e25cf6
- Timestamp:
- 12/01/07 05:09:30 (5 years ago)
- Branch:
- default
- Tags:
- 2.8.15.alpha0
- File:
-
- 1 edited
-
sage/rings/number_field/number_field_base.pyx (modified) (1 diff)
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sage/rings/number_field/number_field_base.pyx
r7437 r7443 159 159 return d * n.factorial() / (n**n) 160 160 161 def signature(self):162 """163 Return (r1, r2), where r1 and r2 are the number of real embeddings164 and pairs of complex embeddings of this field, respectively.165 """166 raise NotImplementedError167 168 def degree(self):169 """170 Return the degree of this number field.171 """172 raise NotImplementedError173 174 def discriminant(self):175 """176 Return the discriminant of this number field.177 """178 raise NotImplementedError179 180 def minkowski_bound(self):181 r"""182 Return the Minkowski bound associated to this number field.183 184 EXAMPLES:185 The Minkowski bound for $\QQ[i]$ tells us that the class186 number is 1:187 sage: K = QQ[I]188 sage: B = K.minkowski_bound(); B189 4/pi190 sage: B.n()191 1.27323954473516192 193 We compute the Minkowski bound for $\QQ[\sqrt[3]{2}]$:194 sage: K = QQ[2^(1/3)]195 sage: B = K.minkowski_bound(); B196 16*sqrt(3)/(3*pi)197 sage: B.n()198 2.94042077558289199 sage: int(B)200 2201 202 We compute the Minkowski bound for $\QQ[\sqrt{10}]$, which203 has class number $2$:204 sage: K = QQ[sqrt(10)]205 sage: B = K.minkowski_bound(); B206 sqrt(10)207 sage: int(B)208 3209 sage: K.class_number()210 2211 212 The bound of course also works for the rational numbers:213 sage: QQ.minkowski_bound()214 1215 """216 _, s = self.signature()217 n = self.degree()218 d = self.discriminant().abs().sqrt()219 from sage.functions.constants import pi220 if s > 0:221 return d * (4/pi)**s * n.factorial() / (n**n)222 else:223 return d * n.factorial() / (n**n)224
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