### Learning-Assisted Reasoning within Proof Assistants

Thibault GauthierPhD thesis, University of Innsbruck, 2018.

### Abstract

One of the aims of artificial intelligence is to be able to solve problems through learning and automated reasoning. Famous examples of intelligent systems can be found in molecular chemistry and games such as chess and Go. The current most successful approaches in these domains combine statistical models trained by machine learning methods with search strategies. However, more abstract problems, generally out of reach of current methods, constructed from abstract principles such as induction appear commonly in mathematics. And proving new theorems often requires to exploit patterns hidden in complex structures. The aim of this thesis is to improve automated reasoning techniques in mathematics. This would help to reduce the time needed for formally proving complex theorems such as the Kepler conjecture. In order for our system to learn from a large number of examples, we align the formal libraries of interactive theorem provers (ITPs) by recognizing similar concepts. The shared knowledge is processed by a statistical model which infers relations between mathematical objects. We exploit those links to produce better strategies for proving theorems. In practice, our project combines ITP knowledge with the search power of automated theorem provers (ATPs). Therefore, if a mathematician states a conjecture in an ITP, our system understands through the statistical model the relation of the conjecture to previously formalized knowledge. It selects theorems relevant for proving the conjecture, simplifies the proof by conjecturing intermediate lemmas and may also guide the proof search by choosing suitable reasoning methods. If successful, it produces a computer-verified proof of the conjecture.

### BibTeX

@phdthesis{TG18, author = "Thibault Gauthier", title = "Learning-Assisted Reasoning within Proof Assistants", school = "University of Innsbruck", year = 2018 }