“…Similar tightening constraints were proposed by Chen and Maravelias . For each ( p , q ) ∈ P × Q , they define sets of good streams in terms of π p , q L and π p , q U as follows .25ex2ex S p , q normalL , normalg ≔ { s ∈ S : π p , q normalL ≤ π s , q } S p , q normalU , normalg ≔ { s ∈ S : π s , q ≤ π p , q normalU } and similarly, sets of bad streams are defined as .25ex2ex S p , q normalL , normalb ≔ { s ∈ S : π p , q normalL > π s , q } S…”