How to get the following ContourPlot
ContourPlot[4 (s + i) - Log[s] + Log[i], {s, 0, 1}, {i, 0, 1}]
over a non rectangular region? First try
ContourPlot[4 (s + i) - Log[s] + Log[i],
Element[{s, i} , {s > 0 && i > 0 && s + i < 1}]]
does not work.


ImplicitRegion:ContourPlot[4 (s + i) - Log[s] + Log[i], Element[{s, i}, ImplicitRegion[{s > 0 && i > 0 && s + i < 1}, {s, i}]]], but this is considerably slower and disables the refinement optionPlotPoints. $\endgroup$