The Quadratic Variation of Gauss-Markov Semimartingales

The covariance function of a Gauss-Markov process evaluated at points $(s,t)$ admits a representation as a product of a function of min(s,t) and a function of max(s,t). We call these functions the covariance factors of a Gauss-Markov process, and give the expression of the quadratic variation of a Gauss-Markov semimartingale in terms of its covariance factors.