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Topic: disjunctive constraints in integer linear programming
Replies: 9   Last Post: Apr 14, 2013 2:43 AM

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quasi

Posts: 10,208
Registered: 7/15/05
Re: disjunctive constraints in integer linear programming
Posted: Apr 12, 2013 5:52 AM
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Ray Vickson wrote:

>If x is real valued (or even rational) the strict inequality
>x < 0 cannot be modelled exactly; instead, one must replace it
>by x <= =e, where e > 0 is "small". If x is also integer (<>0)
>then, of course, x < 0 is the same as x <= -1, so that is
>again OK.


Well, the OP did specify that it was an _integer_ linear program
(actually two such programs the way I interpreted it), so based
on that, the constraint x < 0 is just an alternate way of saying
that x <= -1.

quasi



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