Ilya Sergey
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ilyasergey.bsky.social
Ilya Sergey
@ilyasergey.bsky.social
Associate Professor at National University of Singapore. I do research in programming languages, software verification, distributed systems, and program synthesis. ilyasergey.net
Spent the last couple of days porting my program verification class from Dafny to Lean via Loom/Velvet, and it just works!

Whenever the SMT solver can’t fully prove a program correct, Lean’s aesop and grind take care of the remaining goals.
October 30, 2025 at 11:59 AM
Grokipedia is alright.
October 28, 2025 at 11:10 AM
The tunes of Rocq’n’Roll. #icfpsplash25
October 12, 2025 at 2:09 PM
FARM Performance is about to start! #icfpsplash25
October 12, 2025 at 11:17 AM
I am thrilled to announce Velvet: a new foundational multi-modal verifier for imperative programs in Lean.

Velvet unifies execution, testing, automated and interactive proofs; and is itself proven sound.

💻 github.com/verse-lab/loom
📄 verse-lab.github.io/papers/loom-...
October 9, 2025 at 6:03 AM
Just visited YST Conservatory of NUS, the venue for the upcoming FARM concert at ICFP/SPLASH'25. Excited about the upcoming performance combining art, music, and creative programming!

2025.splashcon.org/track/splash...
September 16, 2025 at 10:06 AM
September 6, 2025 at 6:49 PM
Do it for science!
August 20, 2025 at 2:32 PM
It was a pleasure to host @kcsrk.info who visited NUS earlier this week and talked about some cool systems verification projects done by his team.
August 6, 2025 at 11:44 AM
It was a great pleasure to host Sebastian Ullrich from Lean FRO at NUS and learn about Lean 4 roadmap and its upcoming module system.
July 8, 2025 at 11:24 AM
I really like my job.
June 23, 2025 at 11:37 AM
In Seoul this week. Just got this delicious local treat from a street vendor.
June 16, 2025 at 1:24 PM
One of the cutest small traditions we have in my research lab is, when travelling, to put a flag of the current location into the Mattermost status.
June 11, 2025 at 1:55 PM
One month till POPL deadline.
June 6, 2025 at 9:01 AM
The fact that someone made a one hour video about the flight I take every couple of years and it has been watched 90k times is, probably, a sign that my life is a lot more interesting than I think.

(Also, feeling like a jaded survivor in my regular economy class.)
June 4, 2025 at 10:11 AM
When you are asking Cursor to help with a Lean proof, but it is pissed at you.
May 26, 2025 at 1:37 PM
Jonathan Ragan-Kelley is visiting NUS today, sharing his exciting work on verified user-schedulable languages.
May 21, 2025 at 3:17 AM
May 21, 2025 at 3:15 AM
I’ve had a ton of fun participating in the Working Group 2.8 meeting on Functional Programming last week. Those lambdas are in good hands.
May 20, 2025 at 2:44 AM
Looking forward to visiting MIT CSAIL for the next two days, catching up with the verification folks at PLV and PDOS groups.
May 8, 2025 at 1:57 PM
This is something we've been working on for a while, and now are thrilled to share.

Veil: the first foundational framework that combines SMT-based and interactive proofs about distributed protocols, seamlessly, in Lean!

Tool: github.com/verse-lab/veil
Paper: verse-lab.github.io/papers/veil-...
April 14, 2025 at 8:52 AM
I feel that if I published the main paper of my PhD now, it would be received with much more enthusiasm than it has been back in 2012:
March 31, 2025 at 12:24 PM
“Render this in the style of Studio Ghibli”.
March 30, 2025 at 5:59 PM
According to the GitHub organisation of my research lab, these are the
March 18, 2025 at 6:45 AM
It was great to have @hilacodes.bsky.social visiting NUS over the past few days and educating us on designing interaction models for program synthesis.
March 11, 2025 at 3:52 PM