Do you have any idea how to force an order of Greek letter in the graphics? When I type in
AxesLabel -> {Cost, Δ OverBar[π]} the order is π Δ. How can I force it to be Δ π?
Simply put the label in a string, i.e. between quotes. You can still type any expression you like, including OverBar. From the docs:
OverBar[expr] can be entered using Ctrl+& and _.
Alternatively, wrap the expression in HoldForm or use Row:
AxesLabel -> {Cost, Row[{Δ , OverBar[π]}]} StringForm and Grid. $\endgroup$