Multivariate Force of Mortality
  In usual demographic analysis, force of mortality is a function of one variable, that is, of age. In this article bi-variate and multivariate force of mortality functions are introduced for the first time to explain mortality differentials. The pattern of mortality in a population is one of the strong influencing factors in determining the life expectancies at various ages in the population. Considering univariate functions of age only to understand the human mortality data without associating with other variables could lead to incomplete analysis. The reasons behind declining forces of mortality globally could be studied using the proposed functions. Other applications of multivariate forces of mortality could be in actuarial sciences. 
Swagata Mitra, Pratyush Singh, Arni S. R. Srinivasa Rao
math.DS q-bio.QM