\(t\) time
\(r\) Discount rate
\(V(r)\) Present value
\(C(t)\) A cash flow
\(\delta(t)\) A point mass at time 0
\(a\) A rate of growth or decay
\(\mathcal{L\lbrack}f\rbrack\) The LaPlace transform expressed as operator on a distribution \(f\)
\(F(s)\) The LaPlace transform of distribution \(f(t)\) as a distribution in \(s\)
\(f*g\) The convolution of distributions \(f\) and \(g\)
\(|A|\) The amplitude of a wave
\(\omega\) Wave frequency
\(\theta\) The phase of a wave
\(s\) A complex number
\(i\) \(\sqrt{- 1}\)
\(\alpha\) The real part of a complex number
\(\overline{s}\) The complex conjugate of \(s\)
\(x\) A real number
\(\widetilde{f}\) The Fourier transform of \(f\)
\(\varphi_{X}\) The characteristic function of random variable X
\(N\) The number of observations in a time series
\(x(n)\) An observation of a time series
\(X(k)\) A coefficient of the interpolating series of complex exponentials for \(\omega = 2\pi k/N\)