27
Fractional Permission Session Types
POPL 202754th ACM SIGPLAN Symposium on Principles of Programming Languages.
Ankush Das
Assistant Professor, Department of Computer Science, Boston University
Part-Time Visiting Faculty, NVIDIA
I am recruiting PhD students. My research is in programming languages, with applications to cryptographic protocols, distributed systems, and probabilistic and machine learning models.
Prospective students are encouraged to contact me directly and to apply to the Boston University CS PhD program. Application deadline: December 1, 2026.
My research primarily focuses on programming language foundations with applications to concurrent and distributed systems. More recently, my interests include language design, type systems, cost analysis, and verification for concurrent programs.
I am the lead designer and developer of Nomos, a domain-specific language for smart contracts, and co-designed Rast, a language for resource-aware session types with arithmetic refinements, with Prof. Frank Pfenning.
Before joining Boston University, I was an Applied Scientist at Amazon and previously a Research Fellow at Microsoft Research India. I received my PhD from Carnegie Mellon University in 2021, advised by Prof. Jan Hoffmann, and my undergraduate degree from IIT Bombay in 2015.
Latest News
- Our paper Fractional Permission Session Types has been accepted to POPL 2027!
- Excited to share two workshop papers at PLDI 2026: Testing LLM-Generated Distributed Protocol Code (with Brendan Coyne) at PAgE, and Parametric Choreographies for Distributed Programming (with John Liagouris) at CP.
- I will be attending PLDI 2026 in Boulder, CO! Looking forward to seeing you all there!
- Our submission Practical Refinement Session Type Inference has been accepted to ESOP 2026.
- My undergraduate student Toby Ueno has graduated from Boston University! He is joining University of Edinburgh to pursue his PhD. Best of luck!
- Our submission Probabilistic Refinement Session Types has been accepted to PLDI 2025. Super excited about my first publication as an advisor! Also my first paper at PLDI!
- Excited to host Oregon Programming Language Summer School (OPLSS) at Boston University!
- Our paper Parametric Subtyping for Structural Parametric Polymorphism has been recognized with a distinguished paper award at POPL 2024!
Publications
2027
2026
26
Parametric Choreographies for Distributed Programming
CP 2026Workshop on Choreographic Programming, co-located with PLDI 2026.
25
Testing LLM-Generated Distributed Protocol Code
PAgE 2026Workshop on Principles of Agentic Engineering, co-located with PLDI 2026.
24
2025
23
Probabilistic Refinement Session Types
PLDI 202546th ACM SIGPLAN Conference on Programming Language Design and Implementation.
2024
22
Parametric Subtyping for Structural Parametric Polymorphism
POPL 202451st ACM SIGPLAN Symposium on Principles of Programming Languages.
Distinguished paper award
2023
21
Automated Analyses of IOT Event Monitoring Systems
CAV 2023 (Industrial Experience Report)35th International Conference on Computer Aided Verification.
20
2022
19
Rast: A Language for Resource-Aware Session Types
LMCS 2022Logical Methods in Computer Science, Volume 18, Issue 1.
18
Nested Session Types
TOPLAS 2022ACM Transactions on Programming Languages and Systems, Volume 44, Issue 3.
17
2021
16
15
Resource-Aware Session Types for Digital Contracts
CSF 202134th IEEE Computer Security Foundations Symposium.
2020
14
13
Verified Linear Session-Typed Concurrent Programming
PPDP 202022nd International Symposium on Principles and Practice of Declarative Programming.
12
Session Types with Arithmetic Refinements
CONCUR 202031st International Conference on Concurrency Theory.
11
Rast: Resource-Aware Session Types with Arithmetic Refinements
FSCD 20205th International Conference on Formal Structures for Computation and Deduction.
Best system description paper award by a junior researcher
10
Session Types with Arithmetic Refinements and Their Application to Work Analysis
arXiv Preprint: 2001.04439 [cs.PL]
2018
9
Parallel Complexity Analysis with Temporal Session Types
ICFP 201823rd International Conference on Functional Programming.
8
Work Analysis with Resource-Aware Session Types
LICS 201833rd Annual ACM/IEEE Symposium on Logic in Computer Science.
2017
7
On Petri Nets with Hierarchical Special Arcs
CONCUR 201728th International Conference on Concurrency Theory.
6
Precise Null Pointer Analysis Through Global Value Numbering
ATVA 201715th International Symposium on Automated Technology for Verification and Analysis.
5
ML for ML: Learning Cost Semantics by Experiment
TACAS 201723rd International Conference on Tools and Algorithms for the Construction and Analysis of Systems.
4
Towards Automatic Resource Bound Analysis for OCaml
POPL 201744th ACM SIGPLAN Symposium on Principles of Programming Languages.
2016
3
Learning Cost Semantics for Modeling Running Time of OCaml Programs
LOLA 2016Workshop on Syntax and Semantics of Low-Level Languages
2015
2
Angelic Verification: Precise Verification Modulo Unknowns
CAV 201527th International Conference on Computer Aided Verification.
1
On Pure Nash Equilibria in Stochastic Games
TAMC 201512th Annual Conference on Theory and Applications of Models of Computation.
Current Students
Advised Students
Collaborators and Mentored Students
At Boston University, I’ve had the privilege to work with and mentor a number of fantastic students.
Former Students
- Toby Ueno (undergraduate student, now PhD student at University of Edinburgh)
- Brendan Coyne (undergraduate student)
- Selene Wu (undergraduate student, now PhD student at New York University)
- Qiancheng Fu (PhD student, now postdoc at Cornell University)