Missing } inserted and extra } compile error together?

Question

I have a LaTeX project with the following line:

$$f\left(S_0e^{\left(r-\frac{1}{2}\sigma^2\right)T + \sigma \sqrt{T} x\right)},$$

Without this line, the compilation is ok. With it, there are two errors:

Missing } inserted. ...gma^2\right)T + \sigma \sqrt{T} x\right)}

and immediately after:

Extra }, or forgotten $. ...gma^2\right)T + \sigma \sqrt{T} x\right)}

both for the same, already mentioned line. It seams to me that the compiler inserts a '}' character, and then immediatelly after that it complains about that. Have you ever encountered such a problem?

Answer 1

Your expression starts with a ( followed by a {; it ends with a ), followed by a }.

So when the closing ) is seen, a } is expected, and one is added, so everything balances. But there is still that trailing }, which generates the second error (arguably caused by LaTeX itself).