$$ \ln\left[\Lambda(t \mid \mathbf{x})\right] = s\left(\ln(t) \mid \gamma, \mathbf{k}_{0}\right) + \mathbf{x\beta} $$

$$ R(t) = \exp\left[-\exp\left(\eta\right)\right] $$

$$ F(t) = \int_0^t{S(u)\lambda(u)} du$$