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[0B5](Proposed on 2022-11-24) Note that if we replace \(A\) with
\[ -A = \{ -x : xβ A\} \]
and \(l\) with \( -l\), we switch from the definitions of \(\sup \) to those of \(\inf \) (and vice versa).
[0B5](Proposed on 2022-11-24) Note that if we replace \(A\) with
and \(l\) with \( -l\), we switch from the definitions of \(\sup \) to those of \(\inf \) (and vice versa).