
When not programming or teaching CS @ucsd_cse, I go to the dog beach. https://xitter.cf/t.co/i6J3Qronk4 | https://xitter.cf/t.co/Omunb4WqwB | https://xitter.cf/t.co/iEAaulUul8
San Diego
Joined July 2010
- Tweets5.4K
- Following1.2K
- Followers1.6K
- Likes13.8K
Pinned Tweet
Check out our Assistant Professor position @ucsd_cse!
apol-recruit.ucsd.edu/JPF046…
Since it is 2026, it is worth quoting explicitly from the ad that this not AI-specific: “The department is looking for exceptional candidates in all areas of Computer Science and Engineering.”
Joe Gibbs Politz retweeted
My take on the Airbnb discourse:
Where's the Breakfast? After all, it's in the name!
Joe Gibbs Politz retweeted
Delighted that former postdoc Serge Egelman was a central expert witness in NM's winning case ($25 billion) against Meta for violating state consumer protection laws. Power must be accountable. (And happy that his research w/ me played into his testimony!)
nmdoj.gov/press-release/the-…
One of these papers is now cited in Anthropic’s groundbreaking formal methods post. Claude had to read the \skulls to do its work. These are the career achievements I’m here for.
Joe Gibbs Politz retweeted
Historical moment indeed: formal methods are now verifying real-world binaries at scale! But the specs are single-entry (not API), proofs are huge, and reuse is largely copy-and-adapt. Compositional reasoning and modular abstractions are how the FM community can make this scale.
New on our Frontier Red Team blog: using Claude to formally verify software at large scale.
Formal verification can prove that code is free of certain bugs, but historically it has only been feasible for small codebases (or required a lot of expert time).
With AI models, however, this is beginning to change. In collaboration with @theoremlabs, we used Claude to prove security properties in over one hundred real-world open-source libraries over the span of a few weeks.
Read our research in full here: anthropic.com/research/forma…
Joe Gibbs Politz retweeted
Let me put my TypeScript hat back on for a minute
Content mappers look outrageously exciting. This is now possible:
1. import any non-TypeScript file (markdown, vue, svelte)
2. Write a content mapper to extract types from it
3. Run tsc with --runExternalCode
4. You get type inference from NON TYPESCRIPT CODE
The simplest case:
1. Import a markdown file
2. Add a bit of config to tsconfig.json
3. Run tsc with --runExternalCode
4. Get fully typed markdown frontmatter
Unbelievably useful, a dreamland for tinkerers
TypeScript 7.1 Beta is now available! Now with a preview API, content mapper support, new features, and some great optimizations. Give it a try and give us some feedback! devblogs.microsoft.com/types…
Joe Gibbs Politz retweeted
From the appendix: Claude, in the hands of experts, indirectly attacked the Python semantics by @JoePolitz (OOPSLA 2013) and a random gang of Brown undergrads. Seems like it survived the assault and helped bootstrap a new Claude-verified Python implementation.
New on our Frontier Red Team blog: using Claude to formally verify software at large scale.
Formal verification can prove that code is free of certain bugs, but historically it has only been feasible for small codebases (or required a lot of expert time).
With AI models, however, this is beginning to change. In collaboration with @theoremlabs, we used Claude to prove security properties in over one hundred real-world open-source libraries over the span of a few weeks.
Read our research in full here: anthropic.com/research/forma…
Joe Gibbs Politz retweeted
Replying to @uncle_moon_x @tianyin_xu
大叔还研究这呢?Anthropic 的这个 blog 有一个和我有关的故事,我可以分享一下:
Anthropic 这篇文章里面提到的一个 case study Python interpreter 背后用的一个工具(Appendix里面),是 Brown PLT group 在2013年做的一个叫 lambda py 的语意,一个非常小,适合验证语意的语言,然后把 Python 的语意通过 “desugar” 的形式,“无损”转为 lambda py。后续操作只需要通过 lambda py 进行就行。
如果你知道这个 lambda py 是怎么来的,你一定会惊讶。2013 年,Brown CS 开了一门讲 Programming language 的网课。我那个时候人还在北京刚毕业 gap 了一年,因为很喜欢 compiler,OS等等,不管有用没用,每天下班之后跟他们上网课做作业,网课刚开始一千多人来自全球各地上。大作业之后除了Brown的学生,网课就只有几个人了(论持久战)。而这个网课的后续就是 lambda py。当时的助教带着我们几个人一起把剩下的 Python 语意(module system,metaclass 等等)全部转成 lambda py,写了论文发表,之后大家就散了。而我也机缘巧合从北京小跑到了 Brown 读书,讲课的老师做了我的导师,而我坐在了只在网课上见过的助教旁边。那个时候有点魔幻的感觉。他们今天也给我们发了邮件提起了这篇 blog。lambda py 在13年后的今天被重新用起来。旧事重提,很多事情就又想起来了。
现在的感觉是,过去只是人类力所不及,现在在 LLM 的助攻下,人类可以把过去的砖头全部用上。盖个楼,看这个楼有多高。
Joe Gibbs Politz retweeted
Wild story: the Python semantics Anthropic used was defined at Brown by @JoePolitz and students from a *MOOC*. Summary here, which also explains what Anthropic depends on:
blog.brownplt.org/2013/06/18…
Funnily, the last sentence says, "Once again, machines may put people out of work".
New on our Frontier Red Team blog: using Claude to formally verify software at large scale.
Formal verification can prove that code is free of certain bugs, but historically it has only been feasible for small codebases (or required a lot of expert time).
With AI models, however, this is beginning to change. In collaboration with @theoremlabs, we used Claude to prove security properties in over one hundred real-world open-source libraries over the span of a few weeks.
Read our research in full here: anthropic.com/research/forma…
Joe Gibbs Politz retweeted
Oh, you aren’t updating your dependencies every hour? Well, too bad, you are vulnerable
Oh, you are updating your dependencies every hour? Well, too bad, you are somehow also vulnerable
Kind of cool I can just say “ok I want to make these decisions carefully, and I don’t want to edit the json as it makes my eyes glaze over and I fail to follow through. Take me though the strings I need to edit one at a time” and that just happens.
Joe Gibbs Politz retweeted
Replying to @maiab
The thing I like most about canonical legal names is how many of them I have to choose from.
Joe Gibbs Politz retweeted
Whenever I write a letter to someone, I add a footnote briefly explaining Ohm's law.
It's my P.S. de resistance.
Joe Gibbs Politz retweeted
Replying to @lexi_lambda
A footnote from Stephen Dolan's Algebraic Subtyping, in reference to a paper by Redko: "This paper is out of print, in Russian, and quite difficult to get a hold of, so the interested reader is directed to a shorter proof by Conway [Con71, p. 105], which is merely out of print."
Joe Gibbs Politz retweeted
What happens in a major incident where the frontier models all become unreachable?
This quoted post is unavailable.
Joe Gibbs Politz retweeted
Remember SETI or Fold@Home? We need OpenSource@Home, where we use the tokens that would expire in everyone's subscriptions to contribute to the public good.
Joe Gibbs Politz retweeted
Replying to @garybernhardt
Please develop a deep understanding of the system without looking directly at it.


























