# M2 Presentation ### Introduction slide Notes on my internship ### Plan of the presentation First present what is the subject of my study, and what i tried to achieve. The whole proof is too formal and complex: Informally prove one specific example. Then, i will present the «structure» of the global proof, and show some things discovered along the way ## GAT and 2-sortification ### What is a GAT ### A GAT for a function in set A GAT can be composed of three kinds of lines: - Sort declarations - Objects costructors A model is the data of a function from a set to another set i.e. a triple the data of two sets, and a «mapping» between them We can spice up this GAT: Gat of isomorphic functions. - Equalities ### A GAT for a category Another example of GATs: A category is the data of ...... with ...... such that ...... ### A GAT for Type Theory Last example that of type theory -> a lot to add, contructors, equalities ..., just for the example. ### 2-sortification Known process Used by Sestini Can simplify a study of GATs to only GATs of two sorts ### 2-sortification of the Set function GAT Sort specification is always the same. O will describe «sorts» and El will describe «objects of that sort» Then, we replace Set occuneces by O and we prefix everything else by El ### 2-sortification of the Type Theoyr GAT ### Goal of the internship ## One Example ### Category of Models & Generalization ### Category of models of the Transformed GAT ### Adding transformed sort declarations ### Constructing the functors ### Contsructing G3 ### Constructing F3 ### Adjunction FG ## The complete proof & Discoveries ### Structure of the proof ### Fibration of C ### S from syntax ## Conclusion ### Conclusion ### Future work