Different algorithms for has_rational_point return different answers.
Consider the following snippet:There seems to be an inconsistency.
Define a polynomial ring in three variables:
sage: R.<x, y, z> = QQ[]; QQ[]
Define a conic:
sage: C = Conic(27628*(x^2 - y^2) - 81746*x*y - z^2); print([C.has_rational_point(algorithm = "local", obstruction = True), C.has_rational_point(algorithm = "default", obstruction = True)]);
z^2)
This returns Check whether the conic has rational points, using [(True, None), algorithm="local"
:
sage: C.has_rational_point(algorithm="local", obstruction=True)
(True, None)
Check whether the conic has rational points, using algorithm="default"
:
sage: C.has_rational_point(algorithm="default", obstruction=True)
(False, 17)]17)
.