Re: global assumptions?? How far can I go?

*To*: mathgroup at smc.vnet.net*Subject*: [mg53344] Re: global assumptions?? How far can I go?*From*: Murray Eisenberg <murray at math.umass.edu>*Date*: Thu, 6 Jan 2005 22:00:46 -0500 (EST)*Organization*: Mathematics & Statistics, Univ. of Mass./Amherst*References*: <200501060752.CAA28716@smc.vnet.net>*Reply-to*: murray at math.umass.edu*Sender*: owner-wri-mathgroup at wolfram.com

When I'm using Mathematica in complex analysis, I applaud such "anal" behavior. When I'm doing plain calculus, yes, that gets rather frustrating. For example: Assuming[t â?¥ 0, Integrate[1/(x^2), {x, 1, t}]] If[t > 1, (-1 + t)/t, Integrate[x^(-2), {x, 1, t}, Assumptions -> t <= 1]] That, despite: Integrate[1/x^2, {x, 1, 1}] 0 Integrate[1/x^2, {x, 1, 1/2}] -1 Ron Griffin wrote: > I'm an economist whose accustomed to emphasizing the first orthant in a > noncomplex world (positive, real prices; positive, real, quantities) so > I really get flustered when Mathematica "pollutes" my output with "using inverse > function" warnings and imaginary solutions. > > Now I've "upgraded" to 5.1 from 4.2 and I find, as I expected from my > experience during previous upgrades, that Mathematica is even more anal than it > was before. Hence, programs which ran well under 4.2 now are less > functional because Mathematica is increasingly careful. > > So, how global can I go in telling Mathematica to assume that all the variables > I create are real?? Must I list an assumption for each variable or each > command?? Jees, now it won't even integrate 1/x^2 from 1 to t without > dumping a bunch of worries on me. > > ron > > -- Murray Eisenberg murray at math.umass.edu Mathematics & Statistics Dept. Lederle Graduate Research Tower phone 413 549-1020 (H) University of Massachusetts 413 545-2859 (W) 710 North Pleasant Street fax 413 545-1801 Amherst, MA 01003-9305

**References**:**global assumptions?? How far can I go?***From:*Ron Griffin <ron-griffin@tamu.edu>