I think you have to write '(2Sy < ΔS)and(ΔS < 2m*Sy)' instead of ''2Sy < ΔS < 2mSy''....
Hello, (I'm not 100% sure I understand your question.) I hope this helps: (%i22)...
(I'm not 100% sure I understand your question.) I hope this helps: (%i22) σt(D);...