I wrote an article titled “Exponential Optimizing” for Game Developer, and since it was published a few people wrote to tell me that what I was describing was not exponential, but was actually polynomial.

They are quite correct.  I had mistakenly used “exponential” in the sense of “rapidly increasing”, which is a valid usage, but not too helpful in discussing algorithms.

To be clear, for a variable x, and a constant c,

x^c is polynomial

c^x is exponential.

This is confused a little by the use of n for the variable (as in the number of elements), as n is usually constant.