It is well known that life expectancy can be expressed as an integral of the survival curve. The reverse - that the survival function can be expressed as an integral of life expectancy - is also true.

Half a century ago Strehler and Mildvan (1960) have published the seminal paper that, based on some assumptions (postulates), theoretically ‘justified’ the Gompertz law of mortality. It also defined the, so called, Srehler-Mildvan correlation between the parameters of the Gompertz...