A royal descent is a genealogical line of descent from a past or present monarch. Both geneticists and genealogists have attempted to estimate the percentage of living people with royal descent. From a genetic perspective, the number of unprovable descendants must be virtually unlimited if going back enough generations, according to coalescent theory, as the possibility increases exponentially following every century back in time. In other words, the number of descendants from a monarch increases as a function of the length of time between the monarch's death and the birth of the particular descendant. As for descendants of genealogically documented royal descent, various estimated figures have been proposed. For instance, Mark Humphrys, a professor of computer science at Dublin City Unive