A term structure model with lognormal type volatility structure is proposed. The Heath, Jarrow and Morton (HJM) framework, coupled with the theory of stochastic evolution equations in infinite dimensions, is used to show that the resulting rates are well defined (they do not explode) and remain...

Alternative ways of introducing uncertainty to the term structure of interest rates are considered. They correspond to the different expectation hypotheses. The dynamics of the term structure is analysed in a convenient framework of stochastic equations in infinite dimensions.