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Andrej Bauer

@andrejbauer.mathstodon.xyz.ap.brid.gy

Professor of computational mathematics at University of Ljubljana, Slovenia. [bridged from mathstodon.xyz/@andrejbauer on the fediverse by fed.brid.gy ]

Posts Replies Media

Andrej Bauer @andrejbauer.mathstodon.xyz.ap.brid.gy · 22/06/2026

Human or AI?

C : Carrier
x✝¹ : (Γ : Shape C) ×'
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(_ : Proper Λ) ×'
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(_ : Subst Ψ (Γ ⋈ Θ ⋈ Ω)) ×' (_ : Subst Λ (Γ ⋈ Θ ⋈ Ψ ⋈ Φ)) ×' Expr (Γ ⋈ Λ ⋈ Χ) ⊕'
(Γ : Shape C) ×'
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Andrej Bauer @andrejbauer.mathstodon.xyz.ap.brid.gy · 23/03/2026

Copilot just agrees with every damn thing I ask for. I thought I could reach the bottom, but no.

Savory Rice Casserole with Grasshoppers, Cracklings & Gorgonzola (Honey Finish)
Ingredients

453 g cooked basmati (cold)
120–150 g edible grasshoppers (cleaned)
60–80 g pork cracklings
3 eggs, separated
50 g semolina, 150 ml water
30 g butter (plus for pan) or 2 tbsp oil
80–100 g Gorgonzola dolce, in 1–1.5 cm cubes
Salt, pepper; optional pinch paprika/chili
Breadcrumbs for pan; Finish: 1–2 tbsp honey

Method

Heat oven 180 °C; grease and breadcrumb a baking dish.
Dry‑toast grasshoppers 3–5 min (or 160 °C for 8–10 min); season lightly. Crisp cracklings if needed.
Boil 150 ml water + pinch salt; whisk in 50 g semolina, cook 3–4 min very thick; stir in 30 g butter. Cool to warm.
Whisk yolks with seasoning → stir in warm semolina → fold in rice + 2/3 grasshoppers + 2/3 cracklings.
Beat whites to stiff peaks; gently fold in. Fold in Gorgonzola last (keep cheese pockets).
Spread in pan; top with remaining insects/cracklings; dot with butter/oil. Bake 30–35 min until set and golden. Rest 10 min.
Finish: drizzle 1–2 tbsp honey just before serving.

Go easy on salt—cracklings & Gorgonzola are salty.

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Andrej Bauer @andrejbauer.mathstodon.xyz.ap.brid.gy · 13/04/2025

A while ago I received a phone call from a man who lives in a small Slovenian town. He claimed to have squared the circle, finally after 10 years of efforts. He wanted to come to talk to me about it in Ljubljana. I asked that he first send me his construction […] [Original post on mathstodon.xyz]

An approximate solution to the problem of squaring a circle. The outer square has the side 2√2. The red square is supposed to have size π.

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Andrej Bauer @andrejbauer.mathstodon.xyz.ap.brid.gy · 26/02/2025

It's giving me ideas for very interesting exam questions in category theory that would ask the students to appraise a ChatGPT answer and either confirm it to be correct, or spot the error.

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Andrej Bauer @andrejbauer.mathstodon.xyz.ap.brid.gy · 26/02/2025

Daily reminder on how good ChatGPT is. I asked it to show me the diagrams for 𝑓 : 𝑇𝐴 → 𝐴 being an algebra for the monad 𝑇.

Two diagrams. The left one is labeled "Unit law" and it shows an empty coordinate system with x and y axis in the range from 0 to 1. The right one is labeled "Associativity law" and it shows a graph with four vertices and some arrows involving T, A, μ and f.

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Andrej Bauer @andrejbauer.mathstodon.xyz.ap.brid.gy · 31/01/2025

TIL I made the types.pl logo.

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Andrej Bauer @andrejbauer.mathstodon.xyz.ap.brid.gy · 22/12/2024

I can never remember the formula for the closure operator 𝑗 : 𝖯𝗋𝗈𝗉 → 𝖯𝗋𝗈𝗉 forcing a predicate 𝑃 : 𝐴 → 𝖯𝗋𝗈𝗉 to be true. It is this \\[j(q) = \forall r .\, (q \Rightarrow r) \Rightarrow (\forall x \in A.\, ((P\,x \Rightarrow r) \Rightarrow r) […] [Original post on mathstodon.xyz]

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