Search
Search titles, topics, and the full text of every public entry.
Search and filters
Open filters No filters active
All words must match. Use quotation marks for an exact phrase, such as “halting problem”. Accents are optional.
Select one or more tags. Results must match every selected tag.
No tags match that search.
Results
67 entries, newest first-
notes
Boole and the Algebraic Tradition
How an algebra of classes became a calculus of relations and quantifiers, through Boole, De Morgan, Peirce, and Schröder.
Series: History of Logic #history-of-logic#mathematical-logic#algebraic-logic#history-of-mathematics#boolean-algebra#relations#quantifiers#interactive-labs -
notes
Frege, Quantifiers, and Logical Form
Why variables, scope, and explicit inference changed the representation of mathematical proof, and how Frege's project differed from modern first-order logic.
Series: History of Logic #history-of-logic#mathematical-logic#formal-language#foundations-of-mathematics#quantifiers#first-order-logic#logicism#higher-order-logic#interactive-labs -
notes
Rigor, Infinity, and the Axiomatic Method
How analysis, infinite sets, arithmetic, and alternative geometries changed the questions mathematicians asked about foundations.
Series: History of Logic #history-of-logic#mathematical-logic#foundations-of-mathematics#set-theory#axiomatization#infinity#real-analysis#non-euclidean-geometry#interactive-labs -
notes
Paradoxes and Competing Foundations
Russell's contradiction, Frege's Basic Law V, ramified types, predicativity, and axiomatic set theory as distinct responses to foundational problems.
Series: History of Logic #history-of-logic#mathematical-logic#foundations-of-mathematics#set-theory#type-theory#logicism#paradoxes#russells-paradox#predicativity#axiomatization#interactive-labs -
notes
Hilbert's Program and the Study of Proof
Formalization, finitary reasoning, and the attempt to justify infinitary mathematics through a mathematical analysis of finite derivations.
Series: History of Logic #history-of-logic#mathematical-logic#proof-theory#consistency#foundations-of-mathematics#hilberts-program#finitism#epsilon-calculus#formalization -
notes
Intuitionism and Mathematical Construction
Brouwer, Heyting, constructive evidence, realizability, and the different mathematical programs behind the word constructive.
Series: History of Logic #history-of-logic#mathematical-logic#constructivism#proof-theory#intuitionistic-logic#realizability#classical-logic -
notes
Syntax, Truth, and Completeness
The distinction between derivability and semantic consequence, from formal syntax and Tarski's semantics to Gödel's theorem, Henkin's construction, and nonstandard models.
Series: History of Logic #history-of-logic#mathematical-logic#semantics#model-theory#completeness#first-order-logic#truth#compactness#lowenheim-skolem -
notes
Gödel, Rosser, and Incompleteness
How arithmetic represents proofs, how diagonalization produces an undecidable sentence, and what the two incompleteness theorems establish.
Series: History of Logic #history-of-logic#mathematical-logic#incompleteness#proof-theory#foundations-of-mathematics#godels-theorems#arithmetic#diagonalization#consistency -
notes
The Emergence of Computability
Church, Turing, Kleene, Post, and the mathematical analysis of algorithms, undecidability, relative computation, and Diophantine equations.
Series: History of Logic #history-of-logic#mathematical-logic#computability#algorithms#turing-machines#undecidability#halting-problem#lambda-calculus#interactive-labs -
notes
Gentzen and the Structure of Proof
Natural deduction, sequent calculus, cut elimination, ordinal analysis, and the continuing investigation of the strength and computational content of proofs.
Series: History of Logic #history-of-logic#mathematical-logic#proof-theory#natural-deduction#consistency#reverse-mathematics#sequent-calculus#cut-elimination#ordinal-analysis#interactive-labs -
notes
Model Theory Becomes Mathematics
Definability, quantifier elimination, ultraproducts, nonstandard analysis, and classification as tools for understanding mathematical structures.
Series: History of Logic #history-of-logic#mathematical-logic#model-theory#semantics#definability#quantifier-elimination#ultraproducts#nonstandard-analysis#stability-theory -
notes
Set Theory and Independence
Choice, the continuum hypothesis, Gödel's constructible universe, Cohen's forcing, and the continuing question of which axioms to adopt.
Series: History of Logic #history-of-logic#mathematical-logic#set-theory#independence#foundations-of-mathematics#forcing#continuum-hypothesis#axiom-of-choice#constructibility -
notes
Modal Logic: Necessity, Time, Knowledge, and Provability
How the study of implication developed into a family of logics whose operators express different kinds of necessity.
Series: History of Logic #history-of-logic#mathematical-logic#modal-logic#semantics#kripke-semantics#temporal-logic#epistemic-logic#provability-logic#interactive-labs -
notes
Alternative Logics: Truth, Relevance, Inconsistency, and Resources
Four distinct reasons to reconsider classical inference, illustrated through truth values, relevant implication, inconsistent information, and structural rules.
Series: History of Logic #history-of-logic#mathematical-logic#nonclassical-logic#proof-theory#linear-logic#many-valued-logic#relevance-logic#paraconsistent-logic#structural-rules -
notes
Lambda Calculus and the Curry–Howard Correspondence
How substitution became a theory of computation, and how typed terms came to represent proofs with computational behavior.
Series: History of Logic #history-of-logic#mathematical-logic#lambda-calculus#type-theory#curry-howard#proof-theory#computation#normalization#interactive-labs -
notes
Dependent Type Theory: Proofs, Data, and Universes
How types came to express specifications that depend on values, and why equality, induction, and universe rules became foundational decisions.
Series: History of Logic #history-of-logic#mathematical-logic#dependent-types#foundations-of-mathematics#proof-assistants#type-theory#identity-types#universes#inductive-types -
notes
Categorical Logic: Structure, Quantification, and Internal Languages
How categories provided structural interpretations of proof, function types, quantifiers, and mathematical foundations.
Series: History of Logic #history-of-logic#mathematical-logic#categorical-logic#semantics#foundations-of-mathematics#category-theory#adjunctions#topos-theory#type-theory -
notes
Functional Programming and Programming-Language Semantics
From Lisp and lambda-based language design to mathematical accounts of recursion, polymorphic type inference, and abstraction.
Series: History of Logic #history-of-logic#mathematical-logic#functional-programming#programming-languages#semantics#lambda-calculus#denotational-semantics#type-inference#domain-theory -
notes
Automated Theorem Proving: Clauses, Unification, Equality, and Search
How proof procedures turn a mathematical problem into a search, and why representation, inference rules, and search strategy each matter.
Series: History of Logic #history-of-logic#mathematical-logic#automated-reasoning#resolution#theorem-proving#unification#equality#proof-search#first-order-logic -
notes
Complexity, SAT, and SMT
Why decidable reasoning can be difficult, how conflict-driven solvers exploit structure, and how Boolean search cooperates with mathematical theories.
Series: History of Logic #history-of-logic#mathematical-logic#complexity#sat#smt#automated-reasoning#np-completeness#dpll#cdcl#decision-procedures#interactive-labs -
notes
Logic Programming: Clauses as Programs
How proof search can compute answers, and why a program's logical consequences must be distinguished from the behavior of its execution strategy.
Series: History of Logic #history-of-logic#mathematical-logic#logic-programming#prolog#automated-reasoning#horn-clauses#sld-resolution#datalog#unification -
notes
Proof Assistants: Foundations and Trust
The distinct histories of Automath, LCF, Mizar, inductive provers, dependent-type systems, Metamath, and Lean—and what each architecture asks us to trust.
Series: History of Logic #history-of-logic#mathematical-logic#proof-assistants#formalization#foundations-of-mathematics#type-theory#trusted-kernel#lean#lcf#coq -
notes
Program Verification: Invariants, Semantics, and Local Reasoning
How assertions became a logic of programs, and how proofs of loops, heap operations, compilers, and kernels depend on precise specifications.
Series: History of Logic #history-of-logic#mathematical-logic#program-verification#hoare-logic#separation-logic#formal-methods#loop-invariants#weakest-preconditions#compiler-correctness -
notes
Temporal Verification, Model Checking, and Abstraction
How logics of time became tools for checking ongoing systems, and how symbolic representations and abstraction address the growth of possible behaviors.
Series: History of Logic #history-of-logic#mathematical-logic#model-checking#temporal-logic#abstract-interpretation#formal-methods#safety-and-liveness#symbolic-verification#abstraction#interactive-labs -
notes
Formalized Mathematics: Proofs and Reusable Libraries
How mechanically checked mathematics grew from individual texts and landmark proofs into shared infrastructure for further mathematical work.
Series: History of Logic #history-of-logic#mathematical-logic#formalized-mathematics#mathematical-libraries#proof-assistants#formalization#proof-reflection#mathlib#lean -
notes
Homotopy Type Theory and Univalence
How identity types acquired a geometric interpretation, why equivalence can induce identification, and how cubical theories address computation.
Series: History of Logic #history-of-logic#mathematical-logic#homotopy-type-theory#univalence#foundations-of-mathematics#type-theory#dependent-types#identity-types#cubical-type-theory -
notes
Learned Theorem Proving: Search, Formalization, and Discovery
How statistical guidance works with formal checking, from premise selection to AlphaProof and research formalization, with careful distinctions about evidence and novelty.
Series: History of Logic #history-of-logic#mathematical-logic#ai#theorem-proving#formalization#automated-reasoning#machine-learning#proof-search#autoformalization -
notes
Greek and Late-Antique Logic
Aristotelian demonstration, syllogistic inference, Stoic arguments, and the commentators and translators who shaped their later study.
Series: History of Logic: Earlier Traditions #history-of-logic#ancient-logic#aristotle#stoicism#history-of-philosophy#syllogistic-logic#propositional-logic#demonstration -
notes
Arabic, Islamic, and Jewish Logical Traditions
Translation, demonstration, Avicennan innovations, later teaching traditions, and the movement of logical ideas across Arabic, Hebrew, and Latin.
Series: History of Logic: Earlier Traditions #history-of-logic#arabic-logic#avicenna#medieval-logic#islamic-philosophy#jewish-philosophy#syllogistic-logic#translation -
notes
Medieval Latin Logic: Reference, Consequence, and Paradox
How medieval logicians analyzed the use of terms, the force of logical particles, valid consequences, and self-referential statements.
Series: History of Logic: Earlier Traditions #history-of-logic#medieval-logic#semantics#paradoxes#supposition-theory#logical-consequence#self-reference#history-of-philosophy -
notes
Indian Logic: Inference, Evidence, and Analysis
Nyāya, Buddhist theories of inference, and Navya-Nyāya's technical language, examined through the justification and failure of inferential signs.
Series: History of Logic: Earlier Traditions #history-of-logic#indian-logic#nyaya#buddhist-logic#epistemology#inference#navya-nyaya#history-of-philosophy -
notes
Chinese Traditions of Argument: Names, Kinds, and Distinctions
Mohist standards of reasoning, the School of Names, the white-horse discussion, and Xunzi's account of naming and orderly discourse.
Series: History of Logic: Earlier Traditions #history-of-logic#chinese-philosophy#mohism#argumentation#philosophy-of-language#analogy#school-of-names#history-of-philosophy -
notes
Before Boole: Reform, Leibniz, and Bolzano
Early-modern projects for improving inquiry and calculation, followed by Bolzano's account of propositions, variation, consequence, and explanation.
Series: History of Logic: Earlier Traditions #history-of-logic#early-modern-logic#leibniz#bolzano#induction#logical-consequence#symbolic-logic#history-of-philosophy -
notes
Apex Legends: Game Sense
Notes on the mistakes I keep making in Apex and how I try to stop repeating them. This is only part of game sense, and only the part I have managed to name so far.
#apex-legends#fps#battle-royale#multiplayer#gaming#guide -
notes
History of Logic: Series Guide
Part 0 introduces the series, its reading order, and routes through foundations, computation, formalization, and earlier logical traditions.
Series: History of Logic #history-of-logic#mathematical-logic#foundations-of-mathematics#formalization#history-of-philosophy#interactive-learning -
games
Apex Legends
Everything I have written about Apex Legends, from my settings to notes on how I try to play better.
competitive current #apex-legends#fps#battle-royale#multiplayer#gaming -
notes
Why Mathematical Logic Textbooks Look Circular
Standard textbooks use sets to define first order logic, then define set theory inside first order logic. Where that apparent circularity resolves, and what the metatheory consists of.
#mathematical-logic#logic#foundations#metamathematics#formalism#lean#textbook#mathematics -
notes
Apex Legends: Settings and Gear
The settings, keybinds, sensitivity, and gear I actually play on.
#apex-legends#fps#battle-royale#multiplayer#settings#sensitivity#gear#gaming -
notes
I Switched from WordPress to Astro
Notes from the move off WordPress to a static Astro site, what I gained, and what I gave up.
#ai#astro#blog#design#migration#site#static-site#web-development#website#milestone -
notes
How Separation Resolves Russell's Paradox
Unrestricted comprehension is inconsistent. Separation replaces it, and the relative Russell set is a subset of its base set but never an element of it.
#mathematical-logic#set-theory#logic#foundations#paradox#proof#mathematics -
notes
Why Can't You Solve an Equation by Differentiating Both Sides?
Squaring both sides keeps every original solution, but differentiating does not. The difference comes from the type of the function you apply.
#algebra#chinese#differential-equation#mathematical-logic#mathematics#proof -
notes
Can Lorentz Transformations Be Derived from General Relativity?
How local inertial frames connect Lorentz transformations in special relativity to curved spacetime.
#differential-geometry#general-relativity#manifold#mathematics#metric-space#physics#special-relativity -
notes
Why Does Friction Break Time-Reversal Symmetry?
How microscopic reversibility, probability, and coarse-graining produce macroscopic irreversibility.
#classical-mechanics#loschmidts-paradox#mathematics#paradox#physics#probability#statistical-mechanics#thermodynamics#time-reversal-symmetry -
notes
Why Is the Lorentz Transformation Linear?
A derivation of Lorentz linearity from the structure of inertial frames and spacetime transformations.
#differential-geometry#linear-algebra#manifold#mathematics#physics#special-relativity -
notes
Could the Speed of Light Be Variable?
What the constancy of light speed means, how it is tested, and where variable-speed ideas would have to differ.
#experimental-physics#mathematics#physics#special-relativity#speed-of-light -
notes
Why Are So Many Equations of Motion Second Order?
How first-derivative actions lead to second-order motion, and what Ostrogradsky’s theorem does—and does not—exclude.
#classical-mechanics#differential-equation#lagrangian-mechanics#mathematics#ostrogradsky-instability#physics -
notes
Why Are Phasors Used in Circuit Analysis?
How phasors turn sinusoidal circuit equations into algebra, and what their components represent physically.
#algebra#circuit-analysis#circuits#differential-equation#electromagnetism#linear-algebra#linear-time-invariant#mathematics#phasor#physics#proof -
notes
Intro to Generalized Coordinates
An introduction to generalized coordinates and why they simplify constrained mechanical systems.
#classical-mechanics#introduction#lagrangian-mechanics#mathematics#physics -
notes
A Mathematical Exploration of the Virial Theorem
A derivation and interpretation of the virial theorem through the mathematics of classical mechanics.
#classical-mechanics#introduction#latex#mathematics#physics -
notes
Recommendations for Rigorous Classical Mechanics Textbooks
A reading list for approaching classical mechanics with greater mathematical rigor.
#classical-mechanics#experience#formalism#guide#mathematics#physics#recommendation#textbook -
notes
Why Aren't Generalized Coordinates Treated as Functions of Time?
How partial derivatives of a Lagrangian differ from differentiation along a time-dependent trajectory.
#classical-mechanics#introduction#lagrangian-mechanics#latex#mathematics#physics -
notes
A Mathematical Exploration of Norton's Dome and Determinism in Classical Mechanics
A mathematical look at Norton's dome, non-unique motion, and determinism in classical mechanics.
#chinese#classical-mechanics#differential-equation#introduction#latex#mathematics#paradox#physics -
notes
Why Use Squared Error Rather Than Absolute Error?
A probabilistic and optimization-based explanation of why squared error is so common in loss functions.
#algebra#computer-science#deep-learning#latex#likelihood#machine-learning#mathematics#optimization#probability#probability-theory#regression-analysis#statistics -
notes
Intro to Git, GitHub, and VS Code
A bilingual guide to repositories, forks, clones, branches, commits, and pull requests, with a complete local workflow.
#chinese#computer-science#git#github#guide#introduction#programming#vscode -
notes
Diandian: Two Years After the Rescue
The story of the kitten my family rescued in February 2022, with a 2024 video update.
#chinese#diandian#experience#family#love#pet#video#memory -
notes
Constructing Logic Gates from Truth Tables
Using mathematical logic and Python to reason through a logic-gate construction challenge in Turing Complete.
#coding#computer-science#gaming#introduction#latex#logic#logic-gate#mathematical-logic#mathematics#programming#python -
notes
Using a Raspberry Pi to Build a U.S. VPN Server for My Family in China
A practical record of building a family VPN with Raspberry Pi, SSH, DNS, and Cloudflare.
#cloudflare#coding#computer-science#ddns#dns#github#great-firewall#linux#network#programming#raspberry-pi#server#software#ssh#video#vpn -
notes
I Switched from GitHub Pages to WordPress
Notes from the 2023 move from a Jekyll site on GitHub Pages to WordPress.
#backend#blog#developer#frontend#github#site#web-development#website#milestone -
notes
Competitive Mathematics: Factorization
A structured guide to polynomial factorization, identities, methods, and proofs for mathematical competitions.
#competition#competitive#guide#latex#mathematical-competition#mathematics#notes -
notes
A Guide to Preparing for the William Lowell Putnam Mathematical Competition
Preparation ideas, references, and expectations for the William Lowell Putnam Mathematical Competition.
#competition#competitive#guide#introduction#latex#mathematical-competition#mathematics -
notes
Why Must a Linear Subspace Contain the Additive Identity?
Why nonemptiness and scalar closure force a subspace to contain the ambient zero vector.
#latex#linear-algebra#mathematics#modern-algebra -
notes
A Simple Physical Approach to Understanding the Taylor Series
An intuitive route from motion with changing acceleration to the structure of a Taylor series.
#guide#mathematics#physics#taylor-series -
notes
Intro to the Colemak keyboard layout
A concise introduction to Colemak, its layout choices, and the process of learning it.
#computer-science#introduction#keyboard-layout#typing -
notes
My U.S. Visa Interview in Guangzhou, July 2022
A first-person account of preparing for and completing a U.S. visa interview in Guangzhou.
#chinese#experience -
notes
Summation by Parts (Abel Transformation)
An introduction to summation by parts and its role as the discrete analogue of integration by parts.
#algebra#chinese#introduction#latex#mathematics -
notes
Some Advice for New Python Learners
Practical advice about editors, IDEs, and learning habits for people beginning Python.
#chinese#experience#guide#ide#programming#python#text-editor -
notes
A Simple Analogy to Understand Terminal, Shell, TTY, and Console
A practical mental model for distinguishing terminals, shells, TTYs, and consoles.
#chinese#computer-science#introduction#linux#operating-system
No entries match those filters. Clear one or more filters to widen the result.