[SCIP] Strict Integer Inequalities

[Alex Meiburg]

I noticed that SCIP doesn't seem to like strict inequalities for integers.
When it solves

Maximize
k
st
k < 10
Integer
k

I get the solution

solution status: optimal solution found
objective value:                                   10
k                                                  10 (obj:1)

When of course that's not actually feasible. :) In this case of course it's
pretty simple to remedy by replacing "[foo] < N" by "[foo] <= N-1". But
that's not always valid, e.g. in the problem

Maximize
halfK
st
halfK < 10
halfK + halfK = k
Integer
k

... in which case the correct answer is 9.5 (and SCIP think it's 10). I'm
using SCIP v7.0.2. Is there any interest in fixing this, or at least,
documenting it better...? I skimmed and couldn't find any warnings about
not using strict inequalities.

-- Alexander Meiburg
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