> For the complete documentation index, see [llms.txt](https://b-method.gitbook.io/training-resources-for-atelier-b/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://b-method.gitbook.io/training-resources-for-atelier-b/guides-and-tutorials/applying-the-b-method/mathematical-proof/writing-mathematical-rules/introduction.md).

# Introduction

This section is targeted to users of the prover that need to write mathematical rules to facilitate in the verification of the generated proof obligations. As a matter of fact:

* the proof in predicate logic is undecidable
* the rule base of the prover is finite (it has approximatively 2800 rules)

It may therefore be necessary to add rules, either in a Pmm file or in a PatchProver file.

We draw the attention of the reader on the unfortunate consequences of inadequate rules, that may induce an undesirable behavior of the prover. Particularly, employing false rules enables showing correct false proof obligations and thus jeopardize the development of a correct software.

This section contains advices to write rules that are correct and which verification will be easier to perform.


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