Up to now, my understanding was that if a == b, then hash(a) must be hash(b).
However, this does not necessarily hold in the Fraction Field of Univariate
Polynomial Ring in t over Rational Field, as the following example shows:
sage: R.<q> = QQ[]
sage: a = 1/q
sage: b = 2/(2*q)
sage: hash(a) == hash(b)
False
sage: a == b
True
sage: set([a, b])
set([1/q, 2/(2*q)])
This does not occur over the integers:
sage: R.<z> = ZZ[]
sage: c = 1/z
sage: d = 2/(2*z)
sage: hash(c) == hash(d)
True
sage: c == d
True
sage: set([c, d])
set([1/z])
This does also not occur in the symbolic ring:
sage: var('s')
s
sage: e = 1/s
sage: f = 2/(2*s)
sage: hash(e) == hash(f)
True
sage: e == f
(1/s) == (1/s)
sage: bool(e == f)
True
sage: set([e, f])
set([1/s])
Is this behaviour intentional or is this a bug?
--
You received this message because you are subscribed to the Google Groups
"sage-devel" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
Visit this group at http://groups.google.com/group/sage-devel.
For more options, visit https://groups.google.com/d/optout.
