Thanks Paul, I've tried it but the first column is right aligned and the third is left aligned. I'm kind of new on the subject and the references I have from a friend make them left and right aligned, respectively. Is there an standard way of aligning them? ------------------------------------------------- Julio Rojas jcredbe...@gmail.com

On Wed, Sep 2, 2009 at 5:11 PM, Paul A. Rubin<ru...@msu.edu> wrote: > Julio Rojas wrote: >> >> Thanks, I've already done that, but no option seems to be of help. I'm >> trying to put an integer programing model and every restriction should >> be numbered and aligned like: >> >> Maximize Z (1) >> Subject to: >> Z=sum(Xi) (2) >> Xi+Xj<=1 for all i,j in P, i<j (3) >> Xi,Xj in {0,1} for all i,j in P (4) >> >> So, some rows are numbered, the left column is left aligned and the >> right column is right aligned. How can this numbered array be done? >> ------------------------------------------------- >> Julio Rojas >> jcredbe...@gmail.com >> >> >> >> 2009/9/2 Ignacio García <ignacio.gmora...@gmail.com>: >>> >>> Julio Rojas <jcredbe...@...> writes: >>> >>>> Dear all, is there a way to individually label some equations of an >>>> equation array? Or some rows from an array? >>>> ------------------------------------------------- >>>> Julio Rojas >>>> jcredbe...@... >>>> >>> Please have a look at Help>Math (or Ecuaciones) where you can >>> find a very fine description of this issue in the section 19, >>> 19.3 and/or 19.4. >>> > > Julio, > > Actually, I think what you want is in section 19.1. Inside an equation > array environment, Alt-m n toggles numbering of the entire array (separate > number on each line), while Alt-m Shift-n toggles numbering of just the line > the cursor occupies. > > BTW, I too write integer programs. A while back I came across a reference > to an article ("Avoid eqnarray!" by Lars Madsen, The PracTeX Journal #4, > 2006) that claims that eqnarray is somehow evil. The complaints are mainly > about spacing (including the possibility that equation numbers are > overwritten or crowded off the line). He recommends AMS math environments > or the mathenv package. Then again, I came across a post on sci.op-research > that as I recall advocated eqnarray. > > Anyway, here's an alternative I found somewhere: > > \begin{alignat*}{7} > & \text{maximize } & z= & & 2x_{1} & & + & & 3x_{2} & & + & & 4x_{3}\\ > & \text{subject to: } & & & 44x_{1} & & & & & & + & & 50x_{3} & > \ge900\\ > & & & & & & & & & & & & \llap{\ensuremath{x_{1},x_{2},x_{3}}} & > \ge0 > \end{alignat*} > > FWIW, > Paul > >