  Imagine a website that asks the user to fill in a web form and -- based on
the input values -- derives a relevant figure, for instance an expected salary,
a medical diagnosis or the market value of a house. How to deal with missing
input values at run-time? Besides using fixed defaults, a more sophisticated
approach is to use predefined dependencies (logical or correlational) between
different fields to autofill missing values in an iterative way. Directed
loopless graphs (in which cycles are allowed) are the ideal mathematical model
to formalize these dependencies. We present two new graph-theoretic approaches
to filling missing values at run-time.
