From: SourceForge.net <noreply@so...>  20100925 15:15:03

Bugs item #3075478, was opened at 20100925 14:31 Message generated for change (Comment added) made by crategus You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=3075478&group_id=4933 Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: None Group: None Status: Open Resolution: None Priority: 5 Private: No Submitted By: Barton Willis (willisbl) Assigned to: Nobody/Anonymous (nobody) Summary: is(equal(abs(%i * z + 1),z%i)); Initial Comment: Should be unknown, not false: (%i6) is(equal(abs(%i * z + 1),z%i)); (%o6) false The expressions are equal when z = %i. (%i8) subst(z=%i, abs(%i * z + 1)=z%i); (%o8) 0=0 This is rtest_equal #63  the expected answer is wrong, I think.  >Comment By: Dieter Kaiser (crategus) Date: 20100925 17:15 Message: I think the handling of complex and real expression and symbols is confusing at a lot of places. If we declare a complex or an imaginary symbol the test of this bug report gives the expected results: (%i1) declare(z,complex, j,imaginary)$ (%i3) is(equal(abs(%i*z+1),z+%i)); (%o3) unknown (%i4) is(equal(abs(%i*j+1),j+%i)); (%o4) unknown A symbol not declared to be complex or imaginary is assumed to be real. With this assumption the following test might be called correct too. The symbol x can not have the value %i, it is assumed to be real: (%i5) is(equal(abs(%i*x+1),x+%i)); (%o5) false The problem is that the assumption, that any symbol is real by default sometimes gives the desired results, sometimes not. By the way: The option variable domain does not change anything. This is a problem too. I think a clear concept is missing to get all this right. Dieter Kaiser  You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=3075478&group_id=4933 