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Moritz Schauer

@mschauer.bsky.social
2K followers 1.1K following 288 posts

Statistician, Associate Professor (Lektor) at University of Gothenburg and Chalmers; inference and conditional distributions for anything mschauer.github.io orcid.org/0000-0003-3310-7915 [ˈmoː/r/ɪts ˈʃaʊ̯ɐ]

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Moritz Schauer @mschauer.bsky.social · 03/10/2026
But the spider web itself is implemented using an ad hoc solver of Hooke's law - the solver iteratively moves each free node in the direction of its net force. That is why adding a radius visibly shifts the hub and deforms the frame rather than simply drawing a new straight segment.
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Moritz Schauer @mschauer.bsky.social · 03/10/2026
There are some cinematics in there - the code that generates the impression of a thread moving in the wind is just a really nicely chose parametric curve...
 0.25 * np.sin(2 * PI * (1.5 * s - 0.6 * t)) * s
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Moritz Schauer @mschauer.bsky.social · 03/10/2026
Sick child last week - but the scientifically correct spider net kept us entertained.
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Moritz Schauer @mschauer.bsky.social · 01/07/2026
The redeeming feature is that this price is paid only once.
Right, you don't need error bars on error bars.
Probabilistic uncertainty about uncertainty collapses. This is the “monadic join” in probability.
Instead of a coin with random bias p ∼ π, you can flip a coin with the deterministic bias μ.
Just take μ = E[p].
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Moritz Schauer @mschauer.bsky.social · 06/11/2025
The event B having happened is not the same as the receiving the information O that the event B has happened, because you also condition on receiving the information at all in the latter case. Conflating this contributes a lot to the "paradoxa" such as boy/girl paradox, Monty Hall...
For the applicability of Bayes' theorem, it is important when the information $B$ you condition on is actually available.

Let $O \subset B$ be the event of observing $B$ with $P(O)>0$. If $O$ and $A$ are independent with respect to $P_{|B}(\cdot) = P(\cdot \mid B)$, 
then 
\[
P(A\mid O) = P(A \mid B).
\]
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Moritz Schauer @mschauer.bsky.social · 17/09/2025
Very nice by Jun Otsuka @junotk.bsky.social and Hayato Saigo: link.springer.com/article/10.1... about causal interventions/do calculus via string diagram surgery
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Moritz Schauer @mschauer.bsky.social · 08/08/2025
A golden Marburg Weidenhausen night accentuated by blue paper recycling bins…
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Moritz Schauer @mschauer.bsky.social · 14/07/2025
So this is how I learned programming when I was twelve! 😃
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Moritz Schauer @mschauer.bsky.social · 26/06/2025
Yeah Moritz, *electricity*, that’s totally why you were doing this (bridges for random walks on random graphs)
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Moritz Schauer @mschauer.bsky.social · 18/06/2025
Tomorrow at #BayesComp @rseyer.bsky.social with arxiv.org/abs/2504.12190 (poster presentation, 19 Jun 2025, 5.30pm - 7.30pm local time)
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Moritz Schauer @mschauer.bsky.social · 17/06/2025
Right, you don't need error bars on error bars. Probabilistic uncertainty about uncertainty collapses. This is the “monadic join” in probability. Instead of a coin with random bias p ∼ π, you can flip a coin with the deterministic bias μ. Just take μ = E[p]. #statistics
https://xkcd.com/2110/
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Moritz Schauer @mschauer.bsky.social · 19/04/2025
A paper that started with a twitter conversation and brought us into very unfamiliar terrain is finally submitted with the help of new collaborator Andi Q. Wang: Compositionality in algorithms for smoothing arxiv.org/abs/2303.13865
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Moritz Schauer @mschauer.bsky.social · 08/03/2025
In German a sentence can start with any finite number of „das“: Das “das”, das das “das”, das das “das”, das das “das” in der Basis hat, in der Basis hat, in der Basis hat, ist kaum noch zu erkennen.
Das^das^das^das
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Moritz Schauer @mschauer.bsky.social · 19/01/2025
All of them!
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Moritz Schauer @mschauer.bsky.social · 19/01/2025
Oh, the joy of the truth table of implication! The empty set is like a committee with no members. Each of those non-existing members is found in all other other committees. Each of them is also not found in any other committee.
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Moritz Schauer @mschauer.bsky.social · 08/01/2025
Murphy's 0-1 law…
Tweet text format in Wikipedia style: Murphy's 0-1 law is an epigram that is typically stated as: "Anything that can go wrong will _eventually_ go wrong.
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Moritz Schauer @mschauer.bsky.social · 04/12/2024
So it turns out we don't need to adjust, under the intervention there are no backdoor paths open #causalinference #julialang
Screenshot:

julia> dag = digraph([U=>X, U=>Z, V=>Y, V=>Z, X=>Y, Z=>X])
DiGraph([1 => 3, 1 => 5, 2 => 4, 2 => 5, 3 => 4, 5 => 3])

julia> observed = [X, Y, Z];

julia> do!(dag, Z)

julia> dag
DiGraph([1 => 3, 2 => 4, 3 => 4, 5 => 3])

julia> adjustments = collect(list_covariate_adjustment(dag, X, Y, ∅, observed))
2-element Vector{Any}:
 Set{Int64}()
 Set([5])
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Moritz Schauer @mschauer.bsky.social · 04/12/2024
Cue the bell curve meme with “The probability is 1/6 to get a six” versus “Actually, as the die is already on the table, it is now an unknown but fix number and one is not allowed to talk about the probability to get a six anymore”
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Moritz Schauer @mschauer.bsky.social · 24/11/2024
Mom sends quality content on the family chat 😊. Here is her frozen dress modelling itself
A frozen dress stands by itself
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Moritz Schauer @mschauer.bsky.social · 22/11/2024
In any case you want to think of stochastic or deterministic transport processes `X(p)` where `p` varies.
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Moritz Schauer @mschauer.bsky.social · 16/11/2024
And finally: everything is native Julia, so code is performant AND readable
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Moritz Schauer @mschauer.bsky.social · 16/11/2024
… and state of the art DAGITTY-like adjustment set search for causal effect estimation
Screenshot documentation
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Moritz Schauer @mschauer.bsky.social · 16/11/2024
We also have all the graphical primitives for native Julia graphs: d-separation, Bayes ball, backdoors and front doors, meta-algorithms
Visualisation of Bayesball rules
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Moritz Schauer @mschauer.bsky.social · 16/11/2024
Bingo!
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Moritz Schauer @mschauer.bsky.social · 30/09/2024
The famous Swedish Forrest Penguin (look carefully)
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Moritz Schauer @mschauer.bsky.social · 21/09/2024
For your next conference: how about a poster session in a ferris wheel Photo: Dietmar Rabich / Wikimedia Commons / “Singapore (SG), View from Marina Bay Sands / CC BY-SA 4.0
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Moritz Schauer @mschauer.bsky.social · 17/09/2024
Not a lense effect but really a „smile in the sky“: Amazing #CircumzenithalArc over Gothenburg en.m.wikipedia.org/wiki/Circumz...
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Moritz Schauer @mschauer.bsky.social · 02/11/2023
Take an undirected cycle graph, and orient the edges by coin flip. What is the distribution of sinks? Hint: zero is a special case of an even.
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Moritz Schauer @mschauer.bsky.social · 16/10/2023
Let's resurrect the term "inversion"? Classically, having a prior on X and a forward model giving the conditional probability of observing Y given X, we ask for X given Y. I like the perspective of changing the direction of information flow (from X → Y to Y → X) It generalises so nicely...
Picture shows a DAG with unknown, latents and observable variables.
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Moritz Schauer @mschauer.bsky.social · 08/10/2023
Interpreting a PCA in a causal way has parallels to the Ptolemaic system. I guess the outer circle is the g-factor of Homers shape
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