  This paper continues the line of research aimed at investigating the
relationship between logic programs and first-order theories. We extend the
definition of program completion to programs with input and output in a subset
of the input language of the ASP grounder gringo, study the relationship
between stable models and completion in this context, and describe preliminary
experiments with the use of two software tools, anthem and vampire, for
verifying the correctness of programs with input and output. Proofs of theorems
are based on a lemma that relates the semantics of programs studied in this
paper to stable models of first-order formulas. Under consideration for
acceptance in TPLP.
