@Article{wirthcardinal, author ={Claus-Peter Wirth}, title ={Descente Infinie + {D}eduction}, journal ={Logic Journal of the IGPL}, year ={2004}, pages ={1--96}, volume ={12}, number ={1}, publisher ={Oxford University Press}, note ={{\url{www.ags.uni-sb.de/~cp/p/d}}}, abstract ={Inductive theorem proving in the form of descente infinie was known to the ancient Greeks and is the standard induction method of a working mathematician since it was reinvented in the middle of the 17th century. We present an integration of descente infinie into state-of-the-art free-variable sequent and tableau calculi. It is well-suited for an efficient interplay of human interaction and automation and combines raising, explicit representation of dependence between variables, the liberalized delta-rule, preservation of solutions, and unrestricted applicability of lemmas and induction hypotheses. The semantical requirements are satisfied for a variety of two-valued logics, such as clausal logic, classical first-order logic, and higher-order modal logic.}}