Compare commits
2 commits
e596fe72d8
...
dad12b76a4
Author | SHA1 | Date | |
---|---|---|---|
dad12b76a4 | |||
66478400f7 |
30 changed files with 486 additions and 0 deletions
35
2024/documents/by-course/phil-1/paper-1/package.nix
Normal file
35
2024/documents/by-course/phil-1/paper-1/package.nix
Normal file
|
@ -0,0 +1,35 @@
|
||||||
|
{
|
||||||
|
pkgs,
|
||||||
|
typstPackagesCache,
|
||||||
|
typixLib,
|
||||||
|
cleanTypstSource,
|
||||||
|
...
|
||||||
|
}:
|
||||||
|
let
|
||||||
|
src = cleanTypstSource ./.;
|
||||||
|
commonArgs = {
|
||||||
|
typstSource = "main.typ";
|
||||||
|
|
||||||
|
fontPaths = [
|
||||||
|
# Add paths to fonts here
|
||||||
|
# "${pkgs.roboto}/share/fonts/truetype"
|
||||||
|
];
|
||||||
|
|
||||||
|
virtualPaths = [
|
||||||
|
# Add paths that must be locally accessible to typst here
|
||||||
|
# {
|
||||||
|
# dest = "icons";
|
||||||
|
# src = "${inputs.font-awesome}/svgs/regular";
|
||||||
|
# }
|
||||||
|
];
|
||||||
|
|
||||||
|
XDG_CACHE_HOME = typstPackagesCache;
|
||||||
|
};
|
||||||
|
|
||||||
|
in
|
||||||
|
typixLib.buildTypstProject (
|
||||||
|
commonArgs
|
||||||
|
// {
|
||||||
|
inherit src;
|
||||||
|
}
|
||||||
|
)
|
35
2024/documents/by-name/digression-linear-algebra/package.nix
Normal file
35
2024/documents/by-name/digression-linear-algebra/package.nix
Normal file
|
@ -0,0 +1,35 @@
|
||||||
|
{
|
||||||
|
pkgs,
|
||||||
|
typstPackagesCache,
|
||||||
|
typixLib,
|
||||||
|
cleanTypstSource,
|
||||||
|
...
|
||||||
|
}:
|
||||||
|
let
|
||||||
|
src = cleanTypstSource ./.;
|
||||||
|
commonArgs = {
|
||||||
|
typstSource = "main.typ";
|
||||||
|
|
||||||
|
fontPaths = [
|
||||||
|
# Add paths to fonts here
|
||||||
|
# "${pkgs.roboto}/share/fonts/truetype"
|
||||||
|
];
|
||||||
|
|
||||||
|
virtualPaths = [
|
||||||
|
# Add paths that must be locally accessible to typst here
|
||||||
|
# {
|
||||||
|
# dest = "icons";
|
||||||
|
# src = "${inputs.font-awesome}/svgs/regular";
|
||||||
|
# }
|
||||||
|
];
|
||||||
|
|
||||||
|
XDG_CACHE_HOME = typstPackagesCache;
|
||||||
|
};
|
||||||
|
|
||||||
|
in
|
||||||
|
typixLib.buildTypstProject (
|
||||||
|
commonArgs
|
||||||
|
// {
|
||||||
|
inherit src;
|
||||||
|
}
|
||||||
|
)
|
99
2024/flake.lock
Normal file
99
2024/flake.lock
Normal file
|
@ -0,0 +1,99 @@
|
||||||
|
{
|
||||||
|
"nodes": {
|
||||||
|
"flake-utils": {
|
||||||
|
"inputs": {
|
||||||
|
"systems": "systems"
|
||||||
|
},
|
||||||
|
"locked": {
|
||||||
|
"lastModified": 1726560853,
|
||||||
|
"narHash": "sha256-X6rJYSESBVr3hBoH0WbKE5KvhPU5bloyZ2L4K60/fPQ=",
|
||||||
|
"owner": "numtide",
|
||||||
|
"repo": "flake-utils",
|
||||||
|
"rev": "c1dfcf08411b08f6b8615f7d8971a2bfa81d5e8a",
|
||||||
|
"type": "github"
|
||||||
|
},
|
||||||
|
"original": {
|
||||||
|
"owner": "numtide",
|
||||||
|
"repo": "flake-utils",
|
||||||
|
"type": "github"
|
||||||
|
}
|
||||||
|
},
|
||||||
|
"nixpkgs": {
|
||||||
|
"locked": {
|
||||||
|
"lastModified": 1729256560,
|
||||||
|
"narHash": "sha256-/uilDXvCIEs3C9l73JTACm4quuHUsIHcns1c+cHUJwA=",
|
||||||
|
"owner": "NixOS",
|
||||||
|
"repo": "nixpkgs",
|
||||||
|
"rev": "4c2fcb090b1f3e5b47eaa7bd33913b574a11e0a0",
|
||||||
|
"type": "github"
|
||||||
|
},
|
||||||
|
"original": {
|
||||||
|
"owner": "NixOS",
|
||||||
|
"ref": "nixos-unstable",
|
||||||
|
"repo": "nixpkgs",
|
||||||
|
"type": "github"
|
||||||
|
}
|
||||||
|
},
|
||||||
|
"root": {
|
||||||
|
"inputs": {
|
||||||
|
"flake-utils": "flake-utils",
|
||||||
|
"nixpkgs": "nixpkgs",
|
||||||
|
"typix": "typix",
|
||||||
|
"typst-packages": "typst-packages"
|
||||||
|
}
|
||||||
|
},
|
||||||
|
"systems": {
|
||||||
|
"locked": {
|
||||||
|
"lastModified": 1681028828,
|
||||||
|
"narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
|
||||||
|
"owner": "nix-systems",
|
||||||
|
"repo": "default",
|
||||||
|
"rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
|
||||||
|
"type": "github"
|
||||||
|
},
|
||||||
|
"original": {
|
||||||
|
"owner": "nix-systems",
|
||||||
|
"repo": "default",
|
||||||
|
"type": "github"
|
||||||
|
}
|
||||||
|
},
|
||||||
|
"typix": {
|
||||||
|
"inputs": {
|
||||||
|
"nixpkgs": [
|
||||||
|
"nixpkgs"
|
||||||
|
]
|
||||||
|
},
|
||||||
|
"locked": {
|
||||||
|
"lastModified": 1728290750,
|
||||||
|
"narHash": "sha256-piLZT8398O69hy0e3gX8hUWqSzbCslMCt10pT8d6c8E=",
|
||||||
|
"owner": "loqusion",
|
||||||
|
"repo": "typix",
|
||||||
|
"rev": "62d032735ad32a9a90225c06cb0857677fc753ee",
|
||||||
|
"type": "github"
|
||||||
|
},
|
||||||
|
"original": {
|
||||||
|
"owner": "loqusion",
|
||||||
|
"repo": "typix",
|
||||||
|
"type": "github"
|
||||||
|
}
|
||||||
|
},
|
||||||
|
"typst-packages": {
|
||||||
|
"flake": false,
|
||||||
|
"locked": {
|
||||||
|
"lastModified": 1729252723,
|
||||||
|
"narHash": "sha256-xdaQYNw1GApaJnXJO4WnUTNuYeRXisxIUSuAzVXFEW4=",
|
||||||
|
"owner": "typst",
|
||||||
|
"repo": "packages",
|
||||||
|
"rev": "9bcf190c85da91be6df9f5fc25a93ce5812489cc",
|
||||||
|
"type": "github"
|
||||||
|
},
|
||||||
|
"original": {
|
||||||
|
"owner": "typst",
|
||||||
|
"repo": "packages",
|
||||||
|
"type": "github"
|
||||||
|
}
|
||||||
|
}
|
||||||
|
},
|
||||||
|
"root": "root",
|
||||||
|
"version": 7
|
||||||
|
}
|
92
2024/flake.nix
Normal file
92
2024/flake.nix
Normal file
|
@ -0,0 +1,92 @@
|
||||||
|
{
|
||||||
|
description = "Compiling work in 2024 in a reproducible manner";
|
||||||
|
|
||||||
|
inputs = {
|
||||||
|
nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
|
||||||
|
|
||||||
|
typix = {
|
||||||
|
url = "github:loqusion/typix";
|
||||||
|
inputs.nixpkgs.follows = "nixpkgs";
|
||||||
|
};
|
||||||
|
|
||||||
|
flake-utils.url = "github:numtide/flake-utils";
|
||||||
|
|
||||||
|
typst-packages = {
|
||||||
|
url = "github:typst/packages";
|
||||||
|
flake = false;
|
||||||
|
};
|
||||||
|
|
||||||
|
# Example of downloading icons from a non-flake source
|
||||||
|
# font-awesome = {
|
||||||
|
# url = "github:FortAwesome/Font-Awesome";
|
||||||
|
# flake = false;
|
||||||
|
# };
|
||||||
|
};
|
||||||
|
|
||||||
|
outputs =
|
||||||
|
inputs@{
|
||||||
|
nixpkgs,
|
||||||
|
typix,
|
||||||
|
flake-utils,
|
||||||
|
...
|
||||||
|
}:
|
||||||
|
flake-utils.lib.eachDefaultSystem (
|
||||||
|
system:
|
||||||
|
let
|
||||||
|
pkgs = nixpkgs.legacyPackages.${system};
|
||||||
|
in
|
||||||
|
let
|
||||||
|
typstPackagesSrc = "${inputs.typst-packages}/packages";
|
||||||
|
|
||||||
|
typstPackagesCache = pkgs.stdenv.mkDerivation {
|
||||||
|
name = "typst-packages-cache";
|
||||||
|
src = typstPackagesSrc;
|
||||||
|
dontBuild = true;
|
||||||
|
installPhase = ''
|
||||||
|
mkdir -p "$out/typst/packages"
|
||||||
|
cp -LR --reflink=auto --no-preserve=mode -t "$out/typst/packages" "$src"/*
|
||||||
|
'';
|
||||||
|
};
|
||||||
|
typixLib = typix.lib.${system};
|
||||||
|
in
|
||||||
|
let
|
||||||
|
alexandriaLib = import ./nix/lib {
|
||||||
|
inherit pkgs typixLib typstPackagesCache;
|
||||||
|
};
|
||||||
|
|
||||||
|
in
|
||||||
|
{
|
||||||
|
# checks = {
|
||||||
|
# inherit build-drv build-script watch-script;
|
||||||
|
# };
|
||||||
|
|
||||||
|
legacyPackages = {
|
||||||
|
phil-1 = {
|
||||||
|
paper-1 = alexandriaLib.callTypstProject (import ./documents/by-course/phil-1/paper-1/package.nix);
|
||||||
|
};
|
||||||
|
digression-linear-algebra = alexandriaLib.callTypstProject (import ./documents/by-name/digression-linear-algebra/package.nix);
|
||||||
|
};
|
||||||
|
# apps = rec {
|
||||||
|
# default = watch;
|
||||||
|
# build = flake-utils.lib.mkApp {
|
||||||
|
# drv = build-script;
|
||||||
|
# };
|
||||||
|
# watch = flake-utils.lib.mkApp {
|
||||||
|
# drv = watch-script;
|
||||||
|
# };
|
||||||
|
# };
|
||||||
|
#
|
||||||
|
# devShells.default = typixLib.devShell {
|
||||||
|
# inherit (commonArgs) fontPaths virtualPaths;
|
||||||
|
# packages = [
|
||||||
|
# # WARNING: Don't run `typst-build` directly, instead use `nix run .#build`
|
||||||
|
# # See https://github.com/loqusion/typix/issues/2
|
||||||
|
# # build-script
|
||||||
|
# watch-script
|
||||||
|
# # More packages can be added here, like typstfmt
|
||||||
|
# pkgs.typstyle
|
||||||
|
# ];
|
||||||
|
# };
|
||||||
|
}
|
||||||
|
);
|
||||||
|
}
|
16
2024/nix/lib/callTypstProject.nix
Normal file
16
2024/nix/lib/callTypstProject.nix
Normal file
|
@ -0,0 +1,16 @@
|
||||||
|
{
|
||||||
|
pkgs,
|
||||||
|
typixLib,
|
||||||
|
typstPackagesCache,
|
||||||
|
cleanTypstSource,
|
||||||
|
...
|
||||||
|
}:
|
||||||
|
package:
|
||||||
|
package {
|
||||||
|
inherit
|
||||||
|
pkgs
|
||||||
|
typixLib
|
||||||
|
typstPackagesCache
|
||||||
|
cleanTypstSource
|
||||||
|
;
|
||||||
|
}
|
18
2024/nix/lib/cleanTypstSource.nix
Normal file
18
2024/nix/lib/cleanTypstSource.nix
Normal file
|
@ -0,0 +1,18 @@
|
||||||
|
{ pkgs, ... }:
|
||||||
|
src:
|
||||||
|
let
|
||||||
|
inherit (pkgs) lib;
|
||||||
|
in
|
||||||
|
lib.cleanSourceWith {
|
||||||
|
src = lib.cleanSource src;
|
||||||
|
filter =
|
||||||
|
path: type:
|
||||||
|
let
|
||||||
|
isTypstSource = lib.hasSuffix ".typ" path || lib.hasSuffix ".bib" path;
|
||||||
|
isImage = lib.hasSuffix ".png" path || lib.hasSuffix ".jpeg" path || lib.hasSuffix ".jpg" path;
|
||||||
|
isSpecialFile = builtins.elem (builtins.baseNameOf path) [
|
||||||
|
"typst.toml"
|
||||||
|
];
|
||||||
|
in
|
||||||
|
type == "directory" || isTypstSource || isSpecialFile || isImage;
|
||||||
|
}
|
19
2024/nix/lib/default.nix
Normal file
19
2024/nix/lib/default.nix
Normal file
|
@ -0,0 +1,19 @@
|
||||||
|
{
|
||||||
|
pkgs,
|
||||||
|
typstPackagesCache,
|
||||||
|
typixLib,
|
||||||
|
}:
|
||||||
|
let
|
||||||
|
defaultArgs = {
|
||||||
|
inherit pkgs typstPackagesCache typixLib;
|
||||||
|
};
|
||||||
|
in
|
||||||
|
rec {
|
||||||
|
cleanTypstSource = (import ./cleanTypstSource.nix) defaultArgs;
|
||||||
|
callTypstProject = (import ./callTypstProject.nix) (
|
||||||
|
defaultArgs
|
||||||
|
// {
|
||||||
|
inherit cleanTypstSource;
|
||||||
|
}
|
||||||
|
);
|
||||||
|
}
|
165
2024/notes/math-4a/week-2/main.typ
Normal file
165
2024/notes/math-4a/week-2/main.typ
Normal file
|
@ -0,0 +1,165 @@
|
||||||
|
#import "@preview/unequivocal-ams:0.1.1": ams-article, theorem, proof
|
||||||
|
|
||||||
|
#show: ams-article.with(
|
||||||
|
title: [A Digression on Abstract Linear Algebra],
|
||||||
|
authors: (
|
||||||
|
(
|
||||||
|
name: "Youwen Wu",
|
||||||
|
organization: [University of California, Santa Barbara],
|
||||||
|
email: "youwen@ucsb.edu",
|
||||||
|
url: "https://youwen.dev",
|
||||||
|
),
|
||||||
|
),
|
||||||
|
bibliography: bibliography("refs.bib"),
|
||||||
|
)
|
||||||
|
|
||||||
|
= Introduction
|
||||||
|
|
||||||
|
Many introductory linear algebra classes focus on _application_. In general,
|
||||||
|
this is a red herring and is engineer-speak for "we will teach you how to
|
||||||
|
crunch numbers with no regard for conceptual understanding."
|
||||||
|
|
||||||
|
If you are a math major (or math-adjacent, such as Computer Science), this
|
||||||
|
class is essentially useless for you. You will learn how to perform trivial
|
||||||
|
numerical operations such as the _matrix multiplication_, _matrix-vector
|
||||||
|
multiplication_, _row reduction_, and other trite tasks better suited for
|
||||||
|
computers.
|
||||||
|
|
||||||
|
If you are taking this course, you might as well learn linear algebra properly.
|
||||||
|
Otherwise, you will have to re-learn it later on, anyways. Completing a math
|
||||||
|
course without gaining a theoretical appreciation for the topics at hand is an
|
||||||
|
unequivocal waste of time. I have prepared this brief crash course designed to
|
||||||
|
fill in the theoretical gaps left by this class.
|
||||||
|
|
||||||
|
= Basic Notions
|
||||||
|
|
||||||
|
== Vector spaces
|
||||||
|
|
||||||
|
Before we can understand vectors, we need to first discuss _vector spaces_. Thus
|
||||||
|
far, you have likely encountered vectors primarily in physics classes,
|
||||||
|
generally in the two-dimensional plane. You may conceptualize them as arrows in
|
||||||
|
space. For vectors of size $>3$, a hand waving argument is made that they are
|
||||||
|
essentially just arrows in higher dimensional spaces.
|
||||||
|
|
||||||
|
It is helpful to take a step back from this primitive geometric understanding
|
||||||
|
of the vector. Let us build up a rigorous idea of vectors from first
|
||||||
|
principles.
|
||||||
|
|
||||||
|
=== Vector axioms
|
||||||
|
|
||||||
|
The so-called _axioms_ of a _vector space_ (which we'll call the vector space
|
||||||
|
$V$) are as follows:
|
||||||
|
|
||||||
|
#enum[
|
||||||
|
Commutativity: $u + v = v + u, " " forall u,v in V$
|
||||||
|
][
|
||||||
|
Associativity: $(u + v) + w = u + (v + w), " " forall u,v,w in V$
|
||||||
|
][
|
||||||
|
Zero vector: $exists$ a special vector, denoted $0$, such that $v + 0 = v, " " forall v in V$
|
||||||
|
][
|
||||||
|
Additive inverse: $forall v in V, " " exists w in V "such that" v + w = 0$. Such an additive inverse is generally denoted $-v$
|
||||||
|
][
|
||||||
|
Multiplicative identity: $1 v = v, " " forall v in V$
|
||||||
|
][
|
||||||
|
Multiplicative associativity: $(alpha beta) v = alpha (beta v) " " forall v in V, "scalars" alpha, beta$
|
||||||
|
][
|
||||||
|
Distributive property for vectors: $alpha (u + v) = alpha u + alpha v " " forall u,v in V, "scalars" alpha$
|
||||||
|
][
|
||||||
|
Distributive property for scalars: $(alpha + beta) v = alpha v + beta v " " forall v in V, " scalars" alpha, beta$
|
||||||
|
]
|
||||||
|
|
||||||
|
It is easy to show that the zero vector $0$ and the additive inverse $-v$ are
|
||||||
|
_unique_. We leave the proof of this fact as an exercise.
|
||||||
|
|
||||||
|
These may seem difficult to memorize, but they are essentially the same
|
||||||
|
familiar algebraic properties of numbers you know from high school. The
|
||||||
|
important thing to remember is which operations are valid for what objects. For
|
||||||
|
example, you cannot add a vector and scalar, as it does not make sense.
|
||||||
|
|
||||||
|
_Remark_. For those of you versed in computer science, you may recognize this
|
||||||
|
as essentially saying that you must ensure your operations are _type-safe_.
|
||||||
|
Adding a vector and scalar is not just false, it is an _invalid question_
|
||||||
|
entirely because vectors and scalars and different types of mathematical
|
||||||
|
objects. See #cite(<chen2024digression>, form: "prose") for more.
|
||||||
|
|
||||||
|
=== Vectors big and small
|
||||||
|
|
||||||
|
In order to begin your descent into what mathematicians colloquially recognize
|
||||||
|
as _abstract vapid nonsense_, let's discuss which fields constitute a vector space. We
|
||||||
|
have the familiar space where all scalars are real numbers, or $RR$. We
|
||||||
|
generally discuss 2-D or 3-D vectors, corresponding to vectors of length 2 or
|
||||||
|
3; in our case, $RR^2$ and $RR^3$.
|
||||||
|
|
||||||
|
However, vectors in $RR$ can really be of any length. Discard your primitive
|
||||||
|
conception of vectors as arrows in space. Vectors are simply arbitrary length
|
||||||
|
lists of numbers (for the computer science folk: think C++ `std::vector`).
|
||||||
|
|
||||||
|
_Example_. $ vec(1,2,3,4,5,6,7,8,9) $
|
||||||
|
|
||||||
|
Moreover, vectors need not be in $RR$ at all. Recall that a vector space need
|
||||||
|
only satisfy the aforementioned _axioms of a vector space_.
|
||||||
|
|
||||||
|
_Example_. The vector space $CC$ is similar to $RR$, except it includes complex
|
||||||
|
numbers. All complex vector spaces are real vector spaces (as you can simply
|
||||||
|
restrict them to only use the real numbers), but not the other way around.
|
||||||
|
|
||||||
|
In general, we can have a vector space where the scalars are in an arbitrary
|
||||||
|
field $FF$, as long as the axioms are satisfied.
|
||||||
|
|
||||||
|
_Example_. The vector space of all polynomials of degree 3, or $PP^3$. It is
|
||||||
|
not yet clear what this vector may look like. We shall return to this example
|
||||||
|
once we discuss _basis_.
|
||||||
|
|
||||||
|
== Vector addition. Multiplication
|
||||||
|
|
||||||
|
Vector addition, represented by $+$, and multiplication, represented by the
|
||||||
|
$dot$ (dot) operator, can be done entrywise.
|
||||||
|
|
||||||
|
_Example._
|
||||||
|
|
||||||
|
$
|
||||||
|
vec(1,2,3) + vec(4,5,6) = vec(1 + 4, 2 + 5, 3 + 6) = vec(5,7,9)
|
||||||
|
$
|
||||||
|
$
|
||||||
|
vec(1,2,3) dot vec(4,5,6) = vec(1 dot 4, 2 dot 5, 3 dot 6) = vec(4,10,18)
|
||||||
|
$
|
||||||
|
|
||||||
|
This is simple enough to understand. Again, the difficulty is simply ensuring
|
||||||
|
that you always perform operations with the correct _types_. For example, once
|
||||||
|
we introduce matrices, it doesn't make sense to multiply or add vectors and
|
||||||
|
matrices in this fashion.
|
||||||
|
|
||||||
|
== Vector-scalar multiplication
|
||||||
|
|
||||||
|
Multiplying a vector by a scalar simply results in each entry of the vector
|
||||||
|
being multiplied by the scalar.
|
||||||
|
|
||||||
|
_Example_.
|
||||||
|
|
||||||
|
$ beta vec(a, b, c) = vec(beta dot a, beta dot b, beta dot c) $
|
||||||
|
|
||||||
|
== Matrices
|
||||||
|
|
||||||
|
Before discussing any properties of matrices, let's simply reiterate what we
|
||||||
|
learned in class about their notation. We say a matrix with rows of length $m$,
|
||||||
|
and columns of size $n$ (in less precise terms, a matrix with length $m$ and
|
||||||
|
height $n$) is a $m times n$ matrix.
|
||||||
|
|
||||||
|
Given a matrix
|
||||||
|
|
||||||
|
$ A = mat(1,2,3;4,5,6;7,8,9) $
|
||||||
|
|
||||||
|
we refer to the entry in row $j$ and column $k$ as $A_(j,k)$ .
|
||||||
|
|
||||||
|
=== Matrix transpose
|
||||||
|
|
||||||
|
A formalism that is useful later on is called the _transpose_, and we obtain it
|
||||||
|
from a matrix $A$ by switching all the rows and columns. More precisely, each
|
||||||
|
row becomes a column instead. We use the notation $A^T$ to represent the
|
||||||
|
transpose of $A$.
|
||||||
|
|
||||||
|
$
|
||||||
|
mat(1,2,3;4,5,6)^T = mat(1,4;2,5;3,6)
|
||||||
|
$
|
||||||
|
|
||||||
|
Formally, we can say $(A_(j,k))^T = A_(k,j)$.
|
6
2024/notes/math-4a/week-2/refs.bib
Normal file
6
2024/notes/math-4a/week-2/refs.bib
Normal file
|
@ -0,0 +1,6 @@
|
||||||
|
@misc{chen2024digression,
|
||||||
|
author = {Evan Chen},
|
||||||
|
title = {Digression on Type Safety},
|
||||||
|
year = {2024},
|
||||||
|
howpublished = {\url{https://web.evanchen.cc/upload/1802/tsafe-1802.pdf}},
|
||||||
|
}
|
1
2024/result
Symbolic link
1
2024/result
Symbolic link
|
@ -0,0 +1 @@
|
||||||
|
/nix/store/fv6y2dqv26lw4gzb2pf6ms5hyikpbkm9-typst
|
Loading…
Reference in a new issue