[Help-glpk] glpk wikibook, modeling tips

[Andrew Makhorin]

Robbie,

I noticed an inexactness in the topic
http://en.wikibooks.org/wiki/GLPK/Modeling_tips#Non-convex_functions

You write:

        A nonlinear objective function in the form
        maximize z = min(x1,x2) + min(x3,x4) + ...
        can be modeled as an MIP ...

However, the trick is that in this case you don't need to use binary
variables at all, because you maximize a concave objective function
(this is the same case as if you minimized a convex objective function).
It seems to me that it would be better to consider minimization case,
because it is more obvious.

Best,

Andrew Makhorin