The automatic prover contains general proof mechanisms, which stem from a basis of rules which are not universal.
These mechanisms have been designed in order to solve a large range of proof obligations, principally simple proof obligations. Therefore, the prover has a limited power of resolution.
So as to be able to handle the more difficult cases, it is possible either to orientate the proof by interactive commands (ah,dd, ph, se, ...), or to use manual rules. These rules can correspond to omissions in the rule base. They also allow the user to discharge a proof obligation, during the first step of an interactive proof, by incorporating the proof obligation (in its ”wildcardised” form) in the component pmm file.
This file is located in the same directory as the corresponding component. It should be named with the name of the component and its extension is pmm. It is written in the logic solver language 1.
The rules contained in the .pmm file are loaded by the pc (see chapter 4.35 page §) command and applied by the ar command (see chapter 4.5 page §).
When accessing the .pmm file, the prover displays a message of acceptation of files or an error message.
The rules must be equipped with the trace system (see chapter 10 page §) in order to be used
with the trace system or to appear in the proof tree. If pmm rules are applied and aren’t traced,
the behavior of the proof tree generation module is not guaranteed anymore. Caution!
While the other functions of the interactive prover are fully protected, this possibility of
applying manually written rules is not.
It is possible to enter a false rule, which provokes false demonstration. If no manual rule of this type has been used, then the validity of the demonstrator (automatic+interactive) is sufficient to ensure the validity of the proof, whichever interactive commands have been used.
However, if manual rules have been added, then the user will have to be sure of these rules. The use of a rule demonstrator can be recommended for this task, but it is clear that the interactive prover was designed in order to avoid the use of these manual rules.