Editing Hull–White model (section)

===One-factor model===
The model is a [[short-rate model]]. In general, it has the following dynamics:

:<math>dr(t) = \left[\theta(t) - \alpha(t) r(t)\right]\,dt + \sigma(t)\, dW(t).</math>

There is a degree of ambiguity among practitioners about exactly which parameters in the model are time-dependent or what name to apply to the model in each case. The most commonly accepted naming convention is the following:

*<math>\theta</math> has ''t'' (time) dependence — '''the Hull–White model'''.
*<math>\theta</math> and <math>\alpha</math> are both time-dependent — '''the extended [[Vasicek model]]'''.