Roman Catholic Archdiocese of Tunis to close down all the Catholic churches in the country, forced the Holy See to accept an agreement of the type known as a modus vivendi, a term that literally means "a way of living". This particular agreement was unofficially described as instead a "modus non moriendi" ("a way of not dying"). By it, all but 5 of the country's more than 70 churches were handed over to the state, including what had been the cathedral of the archdiocese, while the state, for its part, promised that the buildings would be put only to use of public interest consonant with
Modus tollens case that Q" (or in brief "not Q"). Then, whenever "formula_6" and "formula_9" each appear by themselves as a line of a proof, then "formula_10" can validly be placed on a subsequent line. The history of the inference rule "modus tollens" goes back to antiquity. "Modus tollens" is closely related to "modus ponens". There are two similar, but invalid, forms of argument: affirming the consequent and denying the antecedent. See also contraposition and proof by contrapositive. The first to explicitly describe the argument form "modus tollens" was Theophrastus. The "modus tollens" rule may be written in sequent notation: where formula_12