Without a sign order of multiple exponents goes from top to bottom: $a^{b^c} = a^{(b^c)}$. But prof says that $e^{-2^2} = e^{-4}$. Like first goes exponentiation $2^2$ than multiplication with a sign.
In my opinion $e^{-2^2}=e^{(-1*2)^2} = e^{(-1)^2*2^2} = e^{1*4}=e^4$. But can't find anything official. Simple calculators just do it consecutively from bottom to top. Haskell does it from top to bottom.
What is the official order of multiple exponents with a sign?