Scott says

Regular readers are sick of this, so just take a vacation and come back next week.  I keep being told that no one’s interested even as I have record volume of viewers.  (Didn’t Yogi Berra say “nobody goes there anymore, it’s too crowded.”)  I’m interested, and I’m the one who decides.

In a perfect world I’d lay out a concise logical proof that Simon Wren-Lewis and Paul Krugman are wrong.  And number each point.  They’d respond saying which of my points were wrong, and why.  Then I’d reply. . . .

Perhaps I can help.

Wren-Lewis said:

DY = DC + DS + DT = DC + DS + DG Λ DG > 0 Λ  -DC <  DT  ==> DY > 0

Which is false.

Proof by example:

Let DG = DT = 2, DC =  -1, and DS = –1

Then both inequalities are satisfied and by the first equation.

DY = –1 –1 + 2 = 0

Which is what we were required to show.