bollu.github.io

• Mathographics: how to draw mathematics
• Method of moving frames
• Learn to draw impossible figures. It’s MUCH harder than I thought it would be.
• Mathematics for physics: has everything including bundles
• Joahn Baez: Gauge Fields, Knots and Gravity
• Probability on trees and networks Some Highlights

Random Walks and Electric Networks Special Networks Uniform Spanning Trees Branching Processes, Second Moments, and Percolation Isoperimetric Inequalities Percolation on Transitive Graphs The Mass-Transport Principle and Percolation Infinite Electrical Networks and Dirichlet Functions Uniform Spanning Forests Minimal Spanning Forests Limit Theorems for Galton-Watson Processes Escape Rate of Random Walks and Embeddings Random Walks on Groups and Poisson Boundaries Hausdorff Dimension Capacity and Stochastic Processes Random Walks on Galton-Watson Trees

• What colour are your bits

My friend had gone through an elaborate process that basically amounted to performing some other piece of music four minutes and thirty-three seconds long, with a software synthesizer and the volume set to zero. The result was an appropriate-sized file of zeroes - which he compressed with an MP3 compressor. The MP3 file was bit-for-bit identical to one that would have been produced by compressing /dev/zero… but this file was (he claimed) legitimately a recording of 4’33” and the other one wouldn’t have been. The difference was the Colour of the bits. He was asserting that the bits in his copy of 433.mp3 had a different Colour from those in a copy of 433.mp3 I might make by means of the /dev/zero procedure, even though the two files would contain exactly the same bits. … The trouble is, human beings are not in general Colour-blind. The law is not Colour-blind. It makes a difference not only what bits you have, but where they came from. There’s a very interesting Web page illustrating the Coloured nature of bits in law on the US Naval Observatory Web site. They provide information on that site about when the Sun rises and sets and so on… but they also provide it under a disclaimer saying that this information is not suitable for use in court. If you need to know when the Sun rose or set for use in a court case, then you need an expert witness - because you don’t actually just need the bits that say when the Sun rose. You need those bits to be Coloured with the Colour that allows them to be admissible in court, and the USNO doesn’t provide that. It’s not just a question of accuracy - we all know perfectly well that the USNO’s numbers are good. It’s a question of where the numbers came from.

• HoTT lecture videos
• Comp.graphics usenet FAQ
• Kobayashi Nomizu: Contains the “"”right definitions””” of all differential geometric objects.
• Reciprocality: The Anatomy, Life Cycle and Effects of the Phenomenologically Distributed Human Parasite M0

This paper presents a self-replicating, homeostatic phenomenon called M0. M0 runs parasitically on populations of humans. It is remarkable in that although its anatomy is distributed across all phenomenological layers from neurological to paradigmattic, its causal sequences are robust and (once exposed) readily traceable and hence vulnerable to counterattack. The anatomy and lifecycle of the parasite are described, together with several secondary effects which are often of primary importance to the host population. An alternative interpretation of the role of dopamine in controlling mood and awareness is proposed, and how the “security breach” thus exposed is exploited by M0 is shown. A disturbing model of the variability of human consciousness is proposed.

• Invitation to topos theory
• Groups, Categories, Homological algebra
• Metric and hilbert spaces
• Cohomology operations and applications in homotopy theory
• Homotopic topology
• Trefethen: Numerical Linear Algebra
• Topology via logic, frames and locales, etc.

• Laziness and linear types mix in complicated ways.

• Spaceship earth

Spaceship Earth (or Spacecraft Earth or Spaceship Planet Earth) is a worldview encouraging everyone on Earth to act as a harmonious crew working toward the greater good. We travel together, passengers on a little space ship, dependent on its vulnerable reserves of air and soil; all committed for our safety to its security and peace; preserved from annihilation only by the care, the work, and, I will say, the love we give our fragile craft. We cannot maintain it half fortunate, half miserable, half confident, half despairing, half slave—to the ancient enemies of man—half free in a liberation of resources undreamed of until this day. No craft, no crew can travel safely with such vast contradictions. On their resolution depends the survival of us all.

• Dialog can change people’s minds

A black man says he has accidentally persuaded around 200 white racists to abandon the Klu Klux Klan simply by befriending them. Blues musician Daryl Davis has travelled the US for around three decades, actively seeking out white supremacists as a hobby. In a new documentary, out this month, the 58-year-old can be seen sitting down beside and joking with cloaked members. “It’s a wonderful thing when you see a light bulb pop on in their heads or they call you and tell you they are quitting,” said the author, actor and lecturer. “I never set out to convert anyone in the Klan. I just set out to get an answer to my question: ‘How can you hate me when you don’t even know me’.

• Jazz standard
• Pannini Projection
• Hunter versus farmer hypothesis

• Gender Differences in Personality and Interests: When, Where, and Why?

How big are gender differences in personality and interests, and how stable are these differences across cultures and over time? To answer these questions, I summarize data from two meta‐analyses and three cross‐cultural studies on gender differences in personality and interests. Results show that gender differences in Big Five personality traits are ‘small’ to ‘moderate,’ with the largest differences occurring for agreeableness and neuroticism (respective ds = 0.40 and 0.34; women higher than men). In contrast, gender differences on the people–things dimension of interests are ‘very large’ (d = 1.18), with women more people‐oriented and less thing‐oriented than men. Gender differences in personality tend to be larger in gender‐egalitarian societies than in gender‐inegalitarian societies, a finding that contradicts social role theory but is consistent with evolutionary, attributional, and social comparison theories. In contrast, gender differences in interests appear to be consistent across cultures and over time, a finding that suggests possible biologic influences.

• Complex analysis: A geometric viewpoint Teaches complex analysis using diffgeo.
• Can’t we talk?

A married couple was in a car when the wife turned to her husband and asked, “Would you like to stop for a coffee?” “No, thanks,” he answered truthfully. So they didn’t stop. The result? The wife, who had indeed wanted to stop, became annoyed because she felt her preference had not been considered. The husband, seeing his wife was angry, became frustrated. Why didn’t she just say what she wanted? Unfortunately, he failed to see that his wife was asking the question not to get an instant decision, but to begin a negotiation. And the woman didn’t realize that when her husband said no, he was just expressing his preference, not making a ruling. When a man and woman interpret the same interchange in such conflicting ways, it’s no wonder they can find themselves leveling angry charges of selfishness and obstinacy at each other. As a specialist in linguistics, I have studied how the conversational styles of men and women differ. We cannot lump all men or all women into fixed categories. But the seemingly senseless misunderstandings that haunt our relationships can in part be explained by the different conversational rules by which men and women play.

• Semantics of type theory
• Selected papers on Automath.
• Higher dimensional type theory
• Differential algebraic topology: From stratifolds to exotic spheres
• Stable homotopy theory
• Computing the continuous discretely: integer point enumeration in polyhedra
• Algebraic Topology of Finite Topological Spaces and Applications by Jonathan Barmak
• Memory layout and staging: https://www.youtube.com/watch?v=WOd0ZFbJfQg
• Concolic execution:
• Determiniant calculus: https://arxiv.org/pdf/math/9902004.pdf
• Compact Oxford english dictionary: https://kk.org/cooltools/compact-oxford/
• Fractional Calculus: An Introduction for Physicists
• Electromagnetic Theory and Computation: A Topological Approach
• Gauge theory and the topology of 4-manifolds
• A history of gale shapely for selecting doctors: https://thesheriffofsodium.com/2020/02/10/the-match-part-3-on-proposals-and-the-fight-for-a-student-optimal-match/
• Being and Event: Dude who claims to use ZFC to “identify the relationship of being to history, Nature, the State, and God”?
• Read quotes of camus, kierkegaard, nietcheze, derrida, lovecraft,
• A Mathematical Introduction to String Theory
• Fundamental Algorithms for Permutation Groups
• Topological data structures for surfaces.
• analytical marxism
• Inuit parenting
• Metamorphosis of prime intellect, author
• Cheap way to spy on someone’s `tty` if they are sharing. Something like `asciinema` but can be live-streamed on a `tty`.
• do-ocracy: an organizational structure in which individuals choose roles and tasks for themselves and execute them.
• SAGE and Ito calculus?: https://github.com/acguidoum/Sim.DiffProc
• https://almostsuremath.com/: great blog on probability
• Apparently, a LOT of complex analysis can be performed if one knows martingales! Examples include “Proof of Liouville’s theorem from Brownian motion”, “Brownian Motion in Complex Analysis”.
• Seems to be a connection between elliptic/parabolic PDEs (heat equation) and brownian motion, which is also ofc explained in keenan’s geodesics in heat. Here is an MO link
• David Williams: Probability with Martingales — motivates probability and measures through martingales.
• arb: a C library for arbitrary precision arithmetic
• James Gilleard: Hypnotic art that looks like a strange blend of natural and artifical. Minimal. He lives in Japan now. Has art on mountains, japan, and animals.