The previous comment brings along my theory (only partially proven yet), which intends to explain our economy using complex numbers (as used in AC circuits). Our money seems to have a "real" part, but some "devices" may make it "imaginary" (locked in banks, where you could only made imaginary transactions with other imaginary accounts); and it is also possible (by means of repetitive multiplication by a complex interest rate) that your "real" money became... negative!
In fact, there are many, many reported cases in which you can open a new account in a bank, deposit $ 1000 in it, then withdraw $ 500, and the balance will be negative (sadly, no joke)
In such an economy, "phase" (timing) is as much as important as "amplitude" (wealth). Indeed, timing may be deemed as more important than the absolute value of a money amount.
Nyquist stability criteria, root locus and such approaches may also be applicable...
Our economy may be a good test field for a HP54V, which could be combination of a HP12C with a HP42S.
From time to time, the issue of a common Mercosur currency appears in the press. Our Brazilian neighbors (Hi!, Luiz and others) have a most appropriate currency sign, the "Real" or "R$". Hence, ours could very well be the "Imaginary Peso", denoted by the "(0+1i)$" expression in rectangular form; or "$;(pi/2)" in polar notation, etc.
