Opened 9 years ago

Last modified 8 years ago

#11309 closed defect

Sage sees -x +y > 0, -y + x >= 0, and x -y > 0 as equivalent — at Initial Version

Reported by: tnv Owned by: burcin
Priority: major Milestone: sage-5.1
Component: symbolics Keywords: inequality equality relational sd31 __richcmp__ sd40.5
Cc: kini, kcrisman, tnv Merged in:
Authors: Reviewers:
Report Upstream: N/A Work issues:
Branch: Commit:
Dependencies: Stopgaps:

Description

-x + y > 0 and x - y > 0 are treated the same in Sage.

sage: version() 'Sage Version 4.6.2, Release Date: 2011-02-25'

sage: (-x +y < 0) in [x -y < 0] True

Set([-x +y >= 0,x -y >= 0]) {-x + y >= 0}

and they have the same Hash

sage: var('x,y') (x, y) sage: hash(-x + y > 0 ) 1221566266 sage: hash(-x + y >= 0 ) 1221566266 sage: hash(x - y >= 0 ) 1221566266 sage: hash(-y + x >= 0 ) 1221566266 sage: hash(x - y > 0 ) 1221566266

It seems to me that Sage treats > , >= , == the same (see http://trac.sagemath.org/sage_trac/ticket/7660). If this is true then it's a serious problem and needs to be addressed.

Change History (0)

Note: See TracTickets for help on using tickets.