This paper studies dynamical and cross-sectional structures of bonds, typically used as riskfreeassets in mathematical finance. After reviewing a mathematical theory on commonfactors, also known as principal components, we compute empirical common factors for 10US government bonds (3month,...

In this paper, we derive a parabolic variational inequality with double time-like variables from a continuous exercise model of American call options proposed in Rogers and Schienkman (2007). Using viscosity approach, we prove that the value function is a unique viscosity solution to the...