PVS # : Streamlined Tacticals for PVS 1 Florent Kirchner

The semantics of a proof language relies on the representation of the state of a proof after a logical rule has been applied. This information, which is usually meaningless from a logical point of view, is fundamental to describe the control mechanism of the proof search provided by the language. In this paper, we propose a datatype, called proof monad, to represent the state information of a proof and we illustrate its use in PVS. Furthermore, we show how this representation can be used to design a new set of powerful PVS tacticals that have simple and clear semantics. The implementation of these tacticals is called PVS#.