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Sariel Har-Peled

@sarielhp.bsky.social
147 followers 80 following 557 posts

A geometer in the corn fields. sarielhp.org

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Sariel Har-Peled @sarielhp.bsky.social · 19/09/2026
I believe the very strong secretary problem on inverted monoids is still open for the next 24 minutes if anyone is looking for a research problem.
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Sariel Har-Peled @sarielhp.bsky.social · 11/09/2026
Tired of LaTeX spewing 500 lines for a missed $? Meet latex_it: 🧹 Clean dirs: build junk stays in junk/ 🎯 Pinpoints exact line where unclosed { or $ began 🚨 Alerts: catches silent bugs (e.g. inverted labels) 🤷 Whatevers: hides sub-mm noise. sarielhp.github.io/latex_it/
sarielhp.github.io
latex_it
Fast, isolated, intelligent LaTeX compilation manager
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Sariel Har-Peled @sarielhp.bsky.social · 10/09/2026
I would like nitty-picky to be an official acceptable phrase in English. Thank you for your attention to this matter.
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Sariel Har-Peled @sarielhp.bsky.social · 30/08/2026
Beware! Octagon ahead!!!
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Sariel Har-Peled @sarielhp.bsky.social · 18/08/2026
I think double blind had been taken too far, when the package tracker refuses to tell you who sent the package, where it is, instead listing anonymous information along the lines "the package had left the hub <timestamp>, arrived at hub <timestamp>, ... arrived to destination country...
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Sariel Har-Peled @sarielhp.bsky.social · 15/08/2026
Outrageous. Such theft is only legal for publishers of academic journals.
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Reposted by Sariel Har-Peled
Darth Putin @darthputinkgb.bsky.social · 06/08/2026
Wildberries is moving to a cloud delivery model.
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Sariel Har-Peled @sarielhp.bsky.social · 02/08/2026
A lot of people making public judgements about math, llms, etc would benefit today from remembering that it is very hard to predict. Especially the future.
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Sariel Har-Peled @sarielhp.bsky.social · 23/07/2026
The failure of reality to follow the analysis of smoothed analysis suggest we need a new reality, not a new type of anslysis. As no new analysis would change the way lp solvers are used in practice.
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Sariel Har-Peled @sarielhp.bsky.social · 21/07/2026
The trump administration to disallow Chinese companies to export advanced llm models to China...
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Sariel Har-Peled @sarielhp.bsky.social · 15/07/2026
Grunbaum's inequality states that for a convex, bounded body K in R^n, let c be its center of mass. Any halfspace containing c contains at least a 1/e fraction of the volume of K. Mind blown...
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Sariel Har-Peled @sarielhp.bsky.social · 15/07/2026
Updated chapter on the Brunn-Minkowski inequality and several interesting applications, including the isoparemeteric inequality and Grunbaum's inequality. sarielhp.org/book/chapter...
sarielhp.org
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Reposted by Sariel Har-Peled
cs-cg-arxiv.bsky.social @cs-cg-arxiv.bsky.social · 14/07/2026
📚 New in arXiv cs.CG: How to Catch $k$ Grid Points
arxiv.org
How to Catch $k$ Grid Points
New paper in cs.CG (Computational Geometry)
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Reposted by Sariel Har-Peled
cs-cg-arxiv.bsky.social @cs-cg-arxiv.bsky.social · 14/07/2026
📚 New in arXiv cs.CG: The Quick Dog Jumps the Log
arxiv.org
The Quick Dog Jumps the Log
New paper in cs.CG (Computational Geometry)
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Sariel Har-Peled @sarielhp.bsky.social · 14/07/2026
arxiv.org/abs/2607.09917
arxiv.org
The Quick Dog Jumps the Log
We give linear-time, and thus optimal, $(1+\varepsilon)$-approximation algorithms for numerous variants of the Frechet distance between $c$-packed curves (where $c \in O(1)$), removing an additional l...
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Sariel Har-Peled @sarielhp.bsky.social · 14/07/2026
arxiv.org/abs/2607.10824
arxiv.org
How to Catch $k$ Grid Points
Given a positive integer $k$, we study the problem of finding a convex polygon of minimum perimeter that encloses exactly $k$ points of $\mathbf{Z}^2$. We show that an optimal polygon is contained in ...
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Sariel Har-Peled @sarielhp.bsky.social · 13/06/2026
Your car is spying on you, and sends the data [location, acceleration, etc] (potentially every few seconds) using its built-in SIMs. True of all new cars starting in 2018. www.bbc.com/future/artic...
bbc.com
Trillions of miles of data: Your car is spying on you, and it's only just the beginning
From your weight and facial expressions to your destination, cars collect a startling amount of data about you. Some of it may even raise your insurance costs.
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Sariel Har-Peled @sarielhp.bsky.social · 10/06/2026
SODA 2027 CFP (www.siam.org/conferences-...) absurdly encourages using a citation style (to avoid using etal) that is in contradiction to *all* writing manuals: sarielhp.org/misc/blog/26... .
siam.org
SODA27 Submissions | SIAM
Submissions for ACM-SIAM Symposium on Discrete Algorithms (SODA27)
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Sariel Har-Peled @sarielhp.bsky.social · 03/06/2026
Behold the new avatar... bsky.app/profile/cs-c...
bsky.app
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Sariel Har-Peled @sarielhp.bsky.social · 29/05/2026
Go tell it to cities in europe....
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Sariel Har-Peled @sarielhp.bsky.social · 21/05/2026
OpenAI is doing an IPO and their technology is impressive. But is it useful? I still have serious doubts about their long term viability compared to say google. I am also wondering if small models might be able to do most targeted tasks equally well, undercutting the whole craze for data centers.
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Sariel Har-Peled @sarielhp.bsky.social · 21/05/2026
Mathematicians rank the hardness of a problem, and thus its importance, by how long it was open and how many people tried to solve it. Its a very strange norm if you think about it....
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Sariel Har-Peled @sarielhp.bsky.social · 20/05/2026
Wow. That is big.
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Sariel Har-Peled @sarielhp.bsky.social · 14/05/2026
Assume you have a discrete distribution, with i having probability p_i, for i=1,..., n, and you have access to a uniform distribution (say on [0,1]). How do you sample from this distribution in constant time? A: The alias method... sarielhp.org/misc/blog/26...
sarielhp.org
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Reposted by Sariel Har-Peled
cs-cg-arxiv.bsky.social @cs-cg-arxiv.bsky.social · 12/05/2026
www.youtube.com/watch?v=h5l7...
youtube.com
Satyan L. Devadoss: Unfolding Polyhedra and Polytopes
YouTube video by Computational Geometry
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Reposted by Sariel Har-Peled
cs-cg-arxiv.bsky.social @cs-cg-arxiv.bsky.social · 12/05/2026
youtu.be/t5kdk8KkAwI
youtu.be
Sergio Cabello: Delaunay Triangulations with Predictions
YouTube video by Computational Geometry
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Sariel Har-Peled @sarielhp.bsky.social · 11/05/2026
Wordle like game, but for arbitrary long words: sarielhp.org/misc/blog/26...
sarielhp.org
Pantaludounboundiglossia
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Sariel Har-Peled @sarielhp.bsky.social · 01/05/2026
There are two computers connected by two wires to each other (via two ports). For example, A1<->B1 and A2<->B2 means that port 1 of A and B are connected by a wire, as well as port 2 of both computers. Alternatively, A1<->B2 and A2<->B1. The two computers are perfectly synchronized.
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Sariel Har-Peled @sarielhp.bsky.social · 29/04/2026
Gemini suggested "Declarative Programmer" as a title for somebody who just programs using Gemini (it is really possible using gemini-cli nowadays). Other suggestions are "Declarative Programmer" and "Gemineer".
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Reposted by Sariel Har-Peled
cs-cg-arxiv.bsky.social @cs-cg-arxiv.bsky.social · 28/04/2026
📚 New in arXiv cs.CG: The Prophet and the Voronoi Diagram
arxiv.org
The Prophet and the Voronoi Diagram
New paper in cs.CG (Computational Geometry)
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Reposted by Sariel Har-Peled
Brandon Barker @nusentry.org · 25/04/2026
www.theverge.com/science/9187... What a miserable time we've created for ourselves.
theverge.com
Trump fires the entire National Science Board
Federal funding for scientific research was already in turmoil.
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Reposted by Sariel Har-Peled
Lance Fortnow @lance.fortnow.com · 15/04/2026
Former NSF theory program director Peter Brass guest posts on the state of the foundation.
blog.computationalcomplexity.org
Guest Post from Peter Brass, Former NSF Theory Director, on the NSF budget.
 Guest post from Peter Brass, Former NSF Theory director (though not affiliated with the NSF now) on the White House NSF budget for FY 2027....
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Sariel Har-Peled @sarielhp.bsky.social · 11/04/2026
It is amazing that you can generate code that generates the following image, by just chatting with an AI agent (gemini-cli in this case)... sarielhp.org/misc/blog/26...
sarielhp.org
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Sariel Har-Peled @sarielhp.bsky.social · 10/04/2026
The Dunning-Kruger-LLM effect is a cognitive bias where people with limited competence in a particular domain overestimate their own abilities since they asked an LLM to explain the domain to them.
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Sariel Har-Peled @sarielhp.bsky.social · 10/04/2026
They are eating the gold bunnies!
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Sariel Har-Peled @sarielhp.bsky.social · 10/04/2026
They are eating the ducks, they are eating the goldfish... www.oxfordstudent.com/2026/02/20/p...
oxfordstudent.com
Péter Magyar: they are eating the ducks! – The Oxford Student
OxStu's Ivett Berényi comments on Péter Magyar's 2026 election campaign and the political situation in Hungary.
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Sariel Har-Peled @sarielhp.bsky.social · 07/04/2026
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cs-cg-arxiv.bsky.social @cs-cg-arxiv.bsky.social · 07/04/2026
📚 New in arXiv cs.CG: Separator for $c$-Packed Segments and Curves
arxiv.org
Separator for $c$-Packed Segments and Curves
New paper in cs.CG (Computational Geometry)
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Sariel Har-Peled @sarielhp.bsky.social · 06/04/2026
Words fail... www.nytimes.com/2026/04/05/u...
nytimes.com
ICE Agents Detain Newlywed Spouse of Soldier Training to Deploy
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Sariel Har-Peled @sarielhp.bsky.social · 04/04/2026
Tesla way of not paying his hotel bill... www.iflscience.com/nikola-tesla...
iflscience.com
Nikola Tesla Once Paid His Hotel Bill With A "Death Ray" Of Unimaginable Power
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Sariel Har-Peled @sarielhp.bsky.social · 02/04/2026
Still uses computers to verify 4-coloring, but still seems like a major step forward on this problem - especially the algorithmic part. At 94 pages, it is not short and simple...
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Reposted by Sariel Har-Peled
cs-cg-arxiv.bsky.social @cs-cg-arxiv.bsky.social · 02/04/2026
📚 New in arXiv cs.CG: Engineering Fully Dynamic Convex Hulls
arxiv.org
Engineering Fully Dynamic Convex Hulls
New paper in cs.CG (Computational Geometry)
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Sariel Har-Peled @sarielhp.bsky.social · 31/03/2026
Rooted trees, not rotted trees.
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Sariel Har-Peled @sarielhp.bsky.social · 26/03/2026
AI strikes again... www.fox13now.com/news/local-n...
fox13now.com
Ribbit ribbit! Artificial Intelligence programs used by Heber City police claim officer turned into a frog
An artificial intelligence that writes police reports had some explaining to do after it claimed earlier this month that a Heber City officer had shape-shifted into a frog.
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Sariel Har-Peled @sarielhp.bsky.social · 25/03/2026
From a paper I am reading...
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Reposted by Sariel Har-Peled
cs-cg-arxiv.bsky.social @cs-cg-arxiv.bsky.social · 24/03/2026
📚 New in arXiv cs.CG: Separators for intersection graphs of spheres
arxiv.org
Separators for intersection graphs of spheres
New paper in cs.CG (Computational Geometry)
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Sariel Har-Peled @sarielhp.bsky.social · 23/03/2026
Demonstrating a one-dimensional linear equation... (Written by gemini-cli). sarielhp.org/misc/blog/26...
sarielhp.org
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Sariel Har-Peled @sarielhp.bsky.social · 21/03/2026
A tip about making a first version of a talk quickly for an existing paper. Copy the LaTeX source to a new directory. Start gemini-cli (or claudecode or opencode or whatever AI CLI tool you have) in this directory. Then tell it to read the paper, and generate a Quarto presentation.
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Sariel Har-Peled @sarielhp.bsky.social · 16/03/2026
QED. Case closed.
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Sariel Har-Peled @sarielhp.bsky.social · 14/03/2026
Its pi day, so here is another "oh really?" about pi. If you pick two random integer numbers in [-N,..., N], the probability they are relatively prime is 6/π^2.
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