We define
and we prove the following:
Using the definite description, we define:
Then using the properties of the definite description, we prove the following propositions.
we add these facts as rewriting rules and we close the definition of case .
We also prove :
case.total.Sum added as introduction rule (abbrev: case , options: -t )
ListChristophe Raffalli, Paul RoziereEquipe de Logique, Université Chambéry, Paris VII