Anja Petković Komel

TU Wien
Favoritenstrasse 11, 1040 Vienna

Anja's photo

About me

I am a postdoctoral researcher under Laura Kovács in the FORSYTE group of informatics department of TU Wien in Vienna, Austria. My main research interests lie in type theory, its applications to proof assistants, automated theorem proving, its applications to blockchain protocols, and logic.

My PhD thesis

Meta-analysis of type theories with an application to the design of formal proofs

I was a PhD student of Andrej Bauer at Faculty of mathematics and physics, University of Ljubljana. In my thesis, I analyze the meta-theory of type theory and its applications to proof assistants. I focus on two aspects: interactions of type theories via transformations and a general user-extensible equality checking algorithm.

One way of studying compatibility of type theories is by looking at their transformations. To accommodate for the use in proof assistants, the transformations we consider are syntactic in nature, they preserve derivability and are general enough to be applicable to a large class of type theories. The transformations preserve some syntactic structure (like judgement kinds and syntactic classes) and they interact nicely with substitutions of variables and instantiations of metavariables: with the action on expressions they form a relative monad for syntax.

A major use case for our definition of type-theoretic transformation is an elaboration. When designing a type theory, especially for using it in a proof assistant, one often faces a dilemma of how verbose the syntax should be. Terms annotated with full typing information are easily amenable to algorithmic processing and have good meta-theoretic properties. However, the syntax can quickly become too verbose to handle, so more economic terms that omit typing information are much more usable in practice. One can also omit other evidence, like proof of termination for recursive functions, or explicit universe levels. One common solution to this problem is to design two type theories: a fully annotated type theory S (the elaboration) that resides in the kernel of the proof assistant and an economic one T for the users input. The theories are connected via two maps: the retrogression transformation (r) that forgets the additional information, and the elaboration map (l) which uses a derivation to construct the missing data. We then prove two theorems: that elaboration is universal and that every finitary type theory has an elaboration. We also investigate some algorithmic properties of elaboration.

Equality checking
Equality checking

Proof assistants based on type theories have equality checking algorithms as their essential components. The algorithms free the users from proving mostly trivial judgemental equalities, and povide computation-by-normalization engines. Some systems, like Agda and Dedukti, allow the users to extend the built-in equality checkers. However, in a proof assistant that supports arbitrary user-definable type theories, like Andromeda 2, an equality checking algorithm highly depends on the given rules or may not even be available. Still, the proof assistant should provide support for equality checking that is easy to use and works well in the common, well-behaved cases. For this purpose we have developed a sound and extensible equality checking algorithm for user-definable type theories. We implemented it in the Andromeda 2 proof assistant.

Publications and talks

Peer-reviewed conferences and journals

Automating Security Analysis of Off-Chain Protocols

with Lea Brugger, Laura Kovács, Sophie Rain, and Michael Rawson

4th International Workshop on Formal Methods for Blockchains

Equality Checking for General Type Theories in Andromeda 2

with Andrej Bauer and Philipp G. Haselwarter

ICMS (2020)

International seminars (mostly peer-reviewed)

The essence of type-theoretic elaboration

Anja Petković Komel,

Women in Logic, 2022

The essence of elaboration

Anja Petković Komel,

Workshop on Syntax and Semantics of Type Thoery, Stockholm, 2022, invited talk

Towards an elaboration theorem

Anja Petković Komel,

HoTT/UF 2021, invited talk

Equality checking for dependent type theories

Andrej Bauer and Anja Petković Komel

TYPES 2021

Equality checking for Finitary type theories

Andrej Bauer, Philipp G. Haselwarter, and Anja Petković

HoTTEST Conference 2020, invited talk

Cancelled On equality checking for general type theories: Implementation in Andromeda 2

Andrej Bauer, Philipp G. Haselwarter, Anja Petković

TYPES 2020

Andromeda 2.0

Anja Petković

Stockholm Logic Seminar




During the four years of my PhD I had the chance to teach the students of mathematics and physics at University of Ljubljana. Besides the courses listed below I conducted a workshop on advanced uses of Mathematica. Prior to that I was a tutor and demonstrator for mathematics and analysis courses at Faculty for mathematics and physics, University of Ljubljana.

Logic and sets (Faculty of Mathematics and Physics, University of Ljubljana)

I was a TA for first year undergraduate mathematics students taking a course on foundations of mathematics: first-order logic and set theory.

  • In autumn 2020, I was a TA for one group and I marked students' exams.
  • In autumn 2019, I was a TA for one group and I marked students' exams.
  • In autumn 2018, I was a TA for one group and I marked students' exams.
  • In autumn 2017, I was a TA for one group and I marked students' exams.

Introduction to programming (Faculty of Mathematics and Physics, University of Ljubljana)

I was a TA for first year undergraduate mathematics and financial mathematics students, givng them an introducotry course on programming in python.

  • In spring 2021, I was a TA for one group and I marked students' exams.
  • In spring 2020, I was a TA for one group and I marked students' projects.
  • In spring 2019, I was a TA for one group and I marked students' exams.

Teaching mathematics and physics in English (Faculty of Mathematics and Physics, University of Ljubljana)

I was a TA for master students in pedagogical mathematics and pedagogical physics. We discussed different approaches to teaching mathematics in English and covered vocabulary for various highschool level topics.

  • In spring 2021, I was a TA for the course I marked students' coursework.

Experience and service


CheckMate is a framework designed to automatically check security properties of games that arise from off-chain (blockchain) protocols. The framework yields a strategy (if it exists) for the following properties: weak immunity, collusion resilience and practicality.

Andromeda is an implementation of (standard) finitary type theories, allowing the user to define their own type theory. It is based on an ML style meta-language that supports proof development via runners and bidirectional evaluation. It implements a user-extensible equality checkig algorithm.

Outreach to society and media

I believe the mission of scientists is not only discovering new science, but also communicating science and science-related issues to others, from fellow scientists to the general public. In October 2022 I gave a talk about gender balance in computer science for students at ENS Paris-Scalay (slides). In June 2022 I participated at a round table about the profession of a scientist, organized by Slovenian national radio station Val 202 (audio). From September 2019 to January 2022 I posed mathematical riddles at the science show Ugriznimo znanost on Slovenian national television RTVSLO. In March 2020 I gave an interview for Metina Lista science podcasts (audio) and in November 2019 an interview at the occasion of 100. anniversary of University of Ljubljana on Slovenian national radio station Val 202 (audio). In December 2018 I co-organised a round table called Women in Science and Technology (video.) with the collegues from Jožef Stefan Institute.