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Sasho Nikolov

@thesasho.bsky.social
2.1K followers 311 following 140 posts

Associate professor at U of Toronto. Computer science and math research: (differentially) private data analysis, geometry, discrepancy, optimization.

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Sasho Nikolov @thesasho.bsky.social · 10/08/2026
Nikhil Bansal and I wrote a book-length survey of algorithmic and geometric methods in discrepancy theory, and a draft of it is online arxiv.org/abs/2608.00140. This book has been years in the making, and I’m excited to share it. More 👇
arxiv.org
Discrepancy Theory: An Algorithmic and Geometric Perspective
Combinatorial discrepancy theory is a subject with roots in combinatorics, geometry, and number theory, and with numerous applications to mathematics and computer science. At its core, discrepancy the...
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Sasho Nikolov @thesasho.bsky.social · 04/06/2026
This sounds pretty cool: bipartite perfect matching is solvable in polylog time in parallel with poly many processors. This was known if you allow randomness but has been a longstanding open problem deterministically.
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Sasho Nikolov @thesasho.bsky.social · 25/05/2026
I have been watching some show set in a university and their version of tenure is wild! One character was hired as a full prof but without tenure (!), and then asked to be placed on the tenure track. The tenure track was sped up just for her from 5 years to 1 year.
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Differential Privacy Papers @dppapers.bsky.social · 13/05/2026
Online Matrix Factorization, Online Private Query Release, and Online Discrepancy Minimization Aleksandar Nikolov, Haohua Tang, Jonathan Ullman arxiv.org/abs/2605.08358
Online Matrix Factorization, Online Private Query Release, and Online Discrepancy Minimization

Aleksandar Nikolov, Haohua Tang, Jonathan Ullman

http://arxiv.org/abs/2605.08358

In this paper we consider several related online computation problems. First, we study answering sequences of statistical queries arriving online, and being answered immediately when they arrive with differential privacy. Known matrix factorization mechanisms can answer a set of statistical queries with error bounded by the $γ_2$ norm of their query matrix, but require that all queries are known in advance. We show that nearly the same error bounds can be achieved in the online setting for non-adaptively chosen queries. To do so, we give an online factorization algorithm that competitively matches the best offline factorization up to logarithmic factors. In the online matrix factorization problem, a new row $q_t$ of a matrix arrives at each time step $t$, and the algorithm needs to maintain a factorization $L_tR_t=Q_t$ such that at each time it appends some rows to $R_t$, and outputs a new row $\ell_t$ s.t. $\ell_tR_t=q_t$. Our algorithm maintains the competitiveness over this online process, even if the number of rows to arrive is unknown. As another application, we give an online discrepancy minimization algorithm that achieves discrepancy competitive against the $γ_2$ norm (and also against hereditary discrepancy) up to logarithmic factors.
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Sasho Nikolov @thesasho.bsky.social · 29/03/2026
Interesting how many people are losing their shit over an innocuous sounding use of AI to make custom feeds.
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Sasho Nikolov @thesasho.bsky.social · 09/03/2026
Changing to daylight savings time feels like I’m going through mini jet lag.
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Sasho Nikolov @thesasho.bsky.social · 17/02/2026
A great read about @henryyuen.bsky.social's research. Also great pictures of him looking thoughtfully into the distance.
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Sasho Nikolov @thesasho.bsky.social · 14/01/2026
I didn't think anyone needed to hear this, but if you are applying for a PhD program, and used an LLM to help write your SoP, check if the papers you cite by the person you say you want to work with actually exist! I remember the titles of my own papers.
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Differential Privacy Papers @dppapers.bsky.social · 01/01/2026
differentialprivacy.org
Call for Papers - TPDP 2026
The 12th Workshop on the Theory and Practice of Differential Privacy (TPDP 2026) will take place on June 1 and 2 in Boston, MA. The deadline to submit a 4-page abstract is February 18, 2026 AoE, with ...
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Alex Bozikovic @alexbozikovic.bsky.social · 10/12/2025
To recap: Doug Ford destroyed parkland at Ontario Place for a private waterpark; closed Ontario Science Centre under false pretenses; and now is moving the OSC into Harbourfront. Partial destruction of one public place; permanent destruction of another; longterm takeover of a third.
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Clément Canonne @ccanonne.github.io · 04/11/2025
Happy #STOC2026 deadline to all who celebrate!
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Sasho Nikolov @thesasho.bsky.social · 04/11/2025
Me to my undergrad students: “Don’t submit 30 secs before the deadline. If you do, don’t complain you missed it.” Also me: pushing submit on a paper at 4:59pm, for a 5pm deadline.
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Sasho Nikolov @thesasho.bsky.social · 02/11/2025
I admit I didn't pay much attention to baseball till this year, although I have been to games. This was wild, and heartbreaking for Toronto. The World Series is not always this dramatic, is it? 18 inning games, wedged balls, being short of a win by a few inches in the last inning..
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CJ Fogler @cjzero.bsky.social · 21/10/2025
The Toronto Blue Jays are going to the World Series
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Colleen @collburns.bsky.social · 09/10/2025
Congratulation to Canada’s Toronto Blue Jays!! 🇨🇦🇨🇦🇨🇦🇨🇦
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Gautam Kamath @gautamkamath.com · 05/09/2025
The great thing about parenting a toddler is that the rest of your day is easy after whatever you've been through by 9 am
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Schwartz Reisman Institute for Technology and Society @torontosri.bsky.social · 04/09/2025
Exciting news from SRI! We’re welcoming Michael Inzlicht & Avery Slater as new research leads for 2025–26! Alongside six continuing leaders, they’ll advance bold projects on AI safety, trust, fairness, creativity & more. Learn more: srinstitute.utoronto.ca/news/eight-n... #AI #UofT
srinstitute.utoronto.ca
Eight research leads drive SRI’s mission forward with new projects — Schwartz Reisman Institute
With two new appointments and six renewed roles, the Schwartz Reisman Institute ’s 2025–26 cohort of research leads will advance projects on trust, creative pedagogy, agentic AI, democratic fairness,...
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Sophie Huiberts @sophie.huiberts.me · 20/08/2025
This is a good feed to have in the mixer. It shows all papers being shared by your follows
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Sasho Nikolov @thesasho.bsky.social · 17/08/2025
The owner of a giant dog that they had unleashed in a children’s playground just did the “but he’s friendly” to my wife and 4yo this morning. The “Please leash your dog at all times” signs are everywhere. This ad is not mean enough IMO.
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Sasho Nikolov @thesasho.bsky.social · 14/08/2025
To test a “quantum computing is impossible” argument, substitute “random bit” for “qubit”, and coins for cats, and see if it sounds silly. E.g.: “N random coins are simultaneously heads/tails and do 2^N work for you to test if a number is prime? Extremely dubious” See, it’s silly!
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Sasho Nikolov @thesasho.bsky.social · 14/08/2025
Great cringe comedy over at the other site.
Pedro Domingos explaining how he doesn’t understand quantum mechanics. From twitter/X
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Sasho Nikolov @thesasho.bsky.social · 13/08/2025
Imagine you are in charge of a playground of 3 year olds, but they are each three meters tall and are throwing rocks at you. It wouldn’t be very hard for them to get around you.
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Sasho Nikolov @thesasho.bsky.social · 28/07/2025
Here is an uplifting song in memory of the greatest that ever got chalk on his coat www.youtube.com/watch?v=frAE...
youtube.com
Tom Lehrer - We Will All Go Together When We Go
YouTube video by The Tom Lehrer Wisdom Channel
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Sasho Nikolov @thesasho.bsky.social · 22/07/2025
Blasting Black Sabbath and remembering seeing them in Sofia in 2005.
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Sasho Nikolov @thesasho.bsky.social · 12/07/2025
Spent the week at an AIM workshop on metric embedding in Caltech, and got to meet many of my mathematical heroes. Also had this view as inspiration.
View of Pasadena and mountains in the back from Caltech Hall.
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Sasho Nikolov @thesasho.bsky.social · 06/07/2025
It’s been 10 years (and 3 days) since I moved to Canada. Lots of things changed in my life in these 10 years, but meeting @theannasu.bsky.social and becoming a dad are the definite highlights!
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Sasho Nikolov @thesasho.bsky.social · 27/06/2025
New profile photo taken by my 4yr old, I think he did a good job!
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Sasho Nikolov @thesasho.bsky.social · 24/06/2025
Was reading a paper on my iPad while eating my lunch and the waitress asked if I was doing my homework. Been a while since I passed for a student!
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Jedwin Mok @jedwinmok.com · 11/06/2025
It's a depressing time in Toronto - a city that once had the continent's most ambitious city-building initiative. This transformation had 3 KEY PILLARS: 1. RapidTO 2. GO Expansion 3. Ontario Line Two pillars have been watered down beyond recognition - DEVASTATING for the region. Here's why: 1/🧵
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Ryan O'Donnell @booleananalysis.bsky.social · 09/06/2025
Spread the word: there is a new prize in Theoretical Computer Science in honor of Luca Trevisan-- cs.unibocconi.eu/call-nominat... (Intent-to-nominate letters due by July 31.)
cs.unibocconi.eu
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Gautam Kamath @gautamkamath.com · 03/06/2025
It's time for the Theory Jobs spreadsheet for 2025! The theory CS community crowdsources who accepted which jobs every year. Links in next post 1/2
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Sasho Nikolov @thesasho.bsky.social · 21/05/2025
The King St streetcar situation right now is a disaster, and it will be a disaster for the whole summer. I am experiencing real whiplash after riding the Tokyo public transit last week.
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Sasho Nikolov @thesasho.bsky.social · 15/05/2025
Our Japan vacation with a preschooler has just been a train ride after train ride and he’s loving it!
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Sasho Nikolov @thesasho.bsky.social · 20/04/2025
Христос Воскресе! Growing up in Bulgaria, Easter meant eating lots of boiled eggs and козунак (sweet eggy Easter bread). Sticking to that in Canada too.
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Connor Ewing @cmewing.bsky.social · 10/04/2025
Me completing my annual review
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Sasho Nikolov @thesasho.bsky.social · 27/02/2025
First time voting in Canada. To support bilingualism I posed in front of the French side of the sign.
Sasho in front of a yellow “Votez” sign for Ontario elections.
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Sasho Nikolov @thesasho.bsky.social · 05/01/2025
I’m trying the “scientific recipe” in this paper next week. Will report back with the results. All for science obviously
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Ira Globus-Harris @iraglobusharris.bsky.social · 05/01/2025
I think this "subscriptionification" of goods and services is the biggest danger tbh. It's already a thing with some goods like printers and I expect will only be more so in time. This in conjunction with planned obsolescence of software support makes me very pessimistic.
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Sasho Nikolov @thesasho.bsky.social · 13/12/2024
This is great, highly recommend going through the slides!
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Sasho Nikolov @thesasho.bsky.social · 09/12/2024
Hey, Berkeley, these numbers don't make sense.
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Sasho Nikolov @thesasho.bsky.social · 08/12/2024
Big if true
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mark lamster @mlamster.bsky.social · 28/11/2024
happy architectural turkey day part II: robarts library at u. toronto, mathers & haldenby, 1973. 🦃🦃🦃
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Kasper Green Larsen @kasperglarsen.bsky.social · 22/11/2024
Recorded an extended version of my MFCS'24 invited talk. The talk presents my personal experiences in entering learning theory with a TCS background. The target audience is mostly TCS researchers. Hope some of you might enjoy it. youtu.be/ZYe2mITwww4
youtu.be
From Theoretical Computer Science to Learning Theory
YouTube video by Kasper Green Larsen
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Clément Canonne @ccanonne.github.io · 25/11/2024
On the TCS job market: Tamalika Mukherjee! Tamalika's research: (1) designing computationally efficient privacy-preserving algorithms for data analysis, (2) understanding their societal implications through the lens of equity and policy. Keywords: sublinear, DP 1/2 #TCSSky #AcademicJobMarket
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Sasho Nikolov @thesasho.bsky.social · 25/11/2024
Teaching NP completeness and gadget reductions reminds how one time I was reading a hardness of approximation paper when a friend came over. My friend saw the section title “The Dictatorship Gadget” and was very concerned
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Anupam Gupta @anupamg.bsky.social · 24/11/2024
Check out this exciting new work by my colleague Subhash Khot, in work with Amey Bhangale, Yang Liu, and Dor MInzer giving improved bounds for the density Hales-Jewett problem, building off their work on approximability of satisfiable CSPs! eccc.weizmann.ac.il/report/2024/...
eccc.weizmann.ac.il
ECCC - TR24-193
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Norm Di Pasquale🇨🇦 @normsworld.bsky.social · 22/11/2024
The world watches incredulously as our Premier puts people who bike’s lives at risk for no good reason except to start a culture war. www.theguardian.com/world/2024/n... #topoli #onpoli #bikeTO
theguardian.com
Removing Toronto bike lanes will make traffic worse, official document shows
In preparation for plan, Ontario has indemnified itself from liability if cyclists are killed on streets that once had bike lanes
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Aaron Roth @aaroth.bsky.social · 18/11/2024
If you are on the job market, and work on the kinds of topics that might be published in FORC ("Foundations of Responsible Computing"), fill out this form and get on the job list. This covers mathematical research on privacy, fairness, and related topics.
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Sasho Nikolov @thesasho.bsky.social · 12/11/2024
I was today years old when I got it
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Lance Fortnow @lance.fortnow.com · 11/11/2024
We asked Russell Impagliazzo to write up his memories of Steven Rudich for our blog. He came back with a very honest and personal seven-page remembrance. fortnow.com/weblog/m... Blog post: blog.computationalco...
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