Jeremy Siek is a Professor of Computer Science in the School of Informatics and Computing at Indiana University. Jeremy teaches courses in programming, programming languages, compilers, logic, and other areas of computer science. Jeremy designs new language features to help programmers create and use software libraries and domain-specific languages, especially generic and high-performance ones. In particular, with Walid Taha, Jeremy invented the *gradual typing* approach to mixing static and dynamic type checking within the same language. Prior to that, Jeremy co-authored the Boost Graph Library and attempted to add *concepts* to C++. Jeremy is a member of the Center for Programming Systems at IU and Jeremy is an Advocate for gender equity.

Email: jsiek@indiana.edu, Office: Luddy Hall 3016, Blog, Twitter, CV, Calendar

## Technology Transfer

I’ve been fortunate to see some of my ideas get used in the software industry:

- Facebook has added gradual typing to PHP. See the article in Wired magazine.

Facebook has also created Flow, a static type checker for JavaScript. - Microsoft created a gradually-typed dialect of JavaScript, called TypeScript.
- The
*implicits*feature of Scala was inspired by my work on*concepts*for C++.

## Sponsors

My group’s research is currently funded by the following sponsors.

- The National Science Foundation awarded the following projects:
- Facebook is supporting us through a Faculty Research Award.

Thank you!

## Recent Papers and Talks

The full list is available on Google Scholar and DBLP. Also, see further below for “authorizer” links to my ACM publications.

*Toward a Mechanized Encyclopedia of Gradual Typing*. Talk at University of Chile. July 2019. slides*Transitivity of Subtyping for Intersection Types*. Draft Paper. June 2019. agda arXiv*Toward Efficient Gradual Typing*. Talk at INRIA Gallium. February 21, 2019. slides*Toward Efficient Gradual Typing for Structural Types via Coercions*, Andre Kuhlenschmidt, Deyaaeldeen Almahallawi, and Jeremy G. Siek. PLDI 2019. pdf. This is an updated version of the below arXiv draft. It adds new performance results but narrows the paper by removing monotonic references.- Gradual typing: a new perspective
Giuseppe Castagna, Victor Lanvin, Tommaso Petrucciani, Jeremy G. Siek

Proceedings of the ACM on Programming Languages, 2019. *The State of the Art in Gradual Typing*,

Talk at the CS Colloquium, Indiana University. slides*Intersection Types, Sub-formula Property, and the Functional Character of the Lambda Calculus*, Talk at IU CPS Meeting slides.*Crash Course on Notation in Programming Language Theory*at LambdaConf 2018. slides video part 1 and part 2*Modeling the Functional Character of the Lambda Calculus*,

Jeremy G. Siek. Isabelle document available here. Also see this

blog post.*Efficient Gradual Typing*, Andre Kuhlenschmidt, Deyaaeldeen Almahallawi, and Jeremy G. Siek. Pre-print on arXiv.*Back to the Future with Denotational Semantics*.

Talk at Off the Beaten Track, Jan. 2018. slides.*Revisiting Elementary Denotational Semantics.*Available on arXiv and in submission, Isabelle mechanization.

## Teaching

- B629: Topics in PL: Denotational Semantics Spring 2018
- C343/H343: Data Structures Fall 2019, Fall 2017, Fall 2016, Fall 2015, Fall 2014, Fall 2013
- P423/P523: Compilers (aka. Programming Language Implementation) Fall 2018, Spring 2016, Spring 2014
- B522: Programming Language Foundations Spring 2015
- C++, Short and Sweet, an Online C++ Course for Beginners at Udemy.

Previous courses at Univ. of Colorado:

- Fall 2012: Compiler Construction
- Fall 2011: Fundamentals of Programming Languages
- Fall 2011: Discrete Mathematics for Computer Engineers
- Spring 2011: Discrete Mathematics for Computer Engineers
- Spring 2011: Theorem Proving in Isabelle
- Fall 2010: Compiler Construction

## Information for Students at IU

- How do I deal with being on a waitlist during course registration?
- What are the requirements for a CS MS degree?
- What are the requirements for a CS PhD degree?

## Students and Post-Doc’s

- Andre Kuhlenschmidt (Ph.D. student, Compilation of Gradually Typed Languages)
- Deyaaeldeen Almahallawi (Ph.D. student, Compilation of Gradually Typed Languages)
- Matthew Heimerdinger (Ph.D. student, Denotational semantics and proofs of compiler correctness)

## Alumni

- Michael M. Vitousek (Facebook, Ph.D. thesis:
*Gradual Typing for Python, Unguarded*) - Chris Wailes (Google, Parallel Programming Languages)
- Matteo Cimini (Assistant Professor, Univ. of Massachusetts Lowell)
- Spenser Bauman (Ph.D. student, Meta-tracing JIT for Racket)
- Di Zhong (Undergraduate Research, now Ph.D. student at Northeastern Univ.)
- Zeina Migeed (Research co-op from Northeastern, now Ph.D. student at UCLA)
- Steev Young (Undergraduate Research in Gradual Typing)
- Josie Bealle (Summer Research Opportunity in Computing)
- Andre Yuri (Summer Research Opportunity in Computing)
- Weiyu Miao (LinkedIn)

Ph.D. thesis:*Reflective Metaprogramming* - Geoffrey Belter (Apple)

Ph.D. thesis:*Efficient Generation of Sequences of Dense Linear Algebra through Auto-Tuning* - Shashank Bharadwaj (VMware)
- Jonathan Turner (Microsoft Typescript => Mozilla Rust)
- Erik Silkensen (Flatiron Solutions)
- Neelam Agrawal (National Instruments)
- Sri Teja Basava (National Instruments)
- Ian Karlin (Postdoc at Lawrence Livermore National Laboratory)
- Justin Gottschlich (Parallel Computing Lab @ Intel Labs)

Ph.D. thesis:*Invalidating Transactions: Optimizations, Theory, Guarantees, and Unification* - Moss Prescott (SlamData)

M.S. thesis:*Speaking for the Trees: a New (Old) Approach to Languages and Syntax* - Christopher Schwaab (Ph.D. student at the Univ. of St. Andrews)
- David Broman (Assoc. Prof. at KTH Royal Inst. of Tech., Sweden)

Ph.D. thesis:*Meta-Languages and Semantics for Equation-Based Modeling and Simulation*

## Authorizor (Free) Links to ACM Publications

- Sound gradual typing: only mostly dead

Spenser Bauman, Carl Friedrich Bolz-Tereick, Jeremy Siek, Sam Tobin-Hochstadt

Proceedings of the ACM on Programming Languages, 2017. - Gradually typed symbolic expressions
David Broman, Jeremy G. Siek

PEPM ’18 Proceedings of the ACM SIGPLAN Workshop on Partial Evaluation and Program Manipulation, 2017 - Theorems for free for free: parametricity, with and without types
Amal Ahmed, Dustin Jamner, Jeremy G. Siek, Philip Wadler

Proceedings of the ACM on Programming Languages, 2017. - Big types in little runtime: open-world soundness and collaborative blame for gradual type systems
Michael M. Vitousek, Cameron Swords, Jeremy G. Siek

POPL 2017 Proceedings of the 44th ACM SIGPLAN Symposium on Principles of Programming Languages, 2017. - Automatically generating the dynamic semantics of gradually typed languages
Matteo Cimini, Jeremy G. Siek

POPL 2017 Proceedings of the 44th ACM SIGPLAN Symposium on Principles of Programming Languages, 2017. - The gradualizer: a methodology and algorithm for generating gradual type systems
Matteo Cimini, Jeremy G. Siek

POPL ’16 Proceedings of the 43rd Annual ACM SIGPLAN-SIGACT Symposium on Principles of Programming Languages, 2016. - Pycket: a tracing JIT for a functional language
Spenser Bauman, Carl Friedrich Bolz, Robert Hirschfeld, Vasily Kirilichev, Tobias Pape, Jeremy G. Siek, Sam Tobin-Hochstadt

ICFP 2015 Proceedings of the 20th ACM SIGPLAN International Conference on Functional Programming, 2015. - Blame and coercion: together again for the first time
Jeremy Siek, Peter Thiemann, Philip Wadler

PLDI ’15 Proceedings of the 36th ACM SIGPLAN Conference on Programming Language Design and Implementation, 2015 - Reliable Generation of High-Performance Matrix Algebra
Thomas Nelson, Geoffrey Belter, Jeremy G. Siek, Elizabeth Jessup, Boyana Norris

ACM Transactions on Mathematical Software (TOMS), 2015. - Design and evaluation of gradual typing for python
Michael M. Vitousek, Andrew M. Kent, Jeremy G. Siek, Jim Baker

DLS ’14 Proceedings of the 10th ACM Symposium on Dynamic languages, 2014 - Interpretations of the gradually-typed lambda calculus
Jeremy G. Siek, Ronald Garcia

Scheme ’12 Proceedings of the 2012 Annual Workshop on Scheme and Functional Programming, 2012. PDF with corrections - Blame for all
Amal Ahmed, Robert Bruce Findler, Jeremy G. Siek, Philip Wadler

ACM SIGPLAN Notices – POPL ’11, 2011. - Threesomes, with and without blame
Jeremy G. Siek, Philip Wadler

POPL ’10 Proceedings of the 37th annual ACM SIGPLAN-SIGACT symposium on Principles of programming languages, 2010. - Gradual typing with unification-based inference
Jeremy G. Siek, Manish Vachharajani

DLS ’08 Proceedings of the 2008 symposium on Dynamic languages, 2008. - Concepts: linguistic support for generic programming in C++
Douglas Gregor, Jaakko Järvi, Jeremy Siek, Bjarne Stroustrup, Gabriel Dos Reis, Andrew Lumsdaine

OOPSLA ’06 Proceedings of the 21st annual ACM SIGPLAN conference on Object-oriented programming systems, languages, and applications, 2006 - Essential language support for generic programming
Jeremy G. Siek, Andrew Lumsdaine

ACM SIGPLAN Notices – Proceedings of the 2005 ACM SIGPLAN conference on Programming language design and implementation, 2005. - A comparative study of language support for generic programming
Ronald Garcia, Jaakko Jarvi, Andrew Lumsdaine, Jeremy G. Siek, Jeremiah Willcock

OOPSLA ’03 Proceedings of the 18th annual ACM SIGPLAN conference on Object-oriented programing, systems, languages, and applications, 2003 - The generic graph component library
Lie-Quan Lee, Jeremy G. Siek, Andrew Lumsdaine

OOPSLA ’99 Proceedings of the 14th ACM SIGPLAN conference on Object-oriented programming, systems, languages, and applications, 1999