Week of notes.

2024-03-15 13:58:15 -04:00 · 2024-03-15 13:58:15 -04:00 · db1d3dd14e
parent cdb916c2b4
commit db1d3dd14e
19 changed files with 480 additions and 27 deletions
--- a/notes/.obsidian/plugins/obsidian-to-anki-plugin/data.json
+++ b/notes/.obsidian/plugins/obsidian-to-anki-plugin/data.json
@ -95,7 +95,8 @@
    "floor-negative.png",
    "floor-positive.png",
    "ceil-positive.png",
-    "ceil-negative.png"
+    "ceil-negative.png",
+    "pascals-triangle.png"
  ],
  "File Hashes": {
    "algorithms/index.md": "cd7c7ba91fb2f961c9f2437777e8e2ac",
@ -139,7 +140,7 @@
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    "algorithms/loop-invariant.md": "29f9f9090a3109890d333a78acc18b50",
    "algorithms/running-time.md": "5efc0791097d2c996f931c9046c95f65",
-    "algorithms/order-growth.md": "80801ebb1a9142150699b05b0b41d819",
+    "algorithms/order-growth.md": "0148c1e9f4aa89cc8a7fcf44666805d0",
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    "algorithms/index 1.md": "6fada1f3d5d3af64687719eb465a5b97",
@ -147,7 +148,7 @@
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    "_journal/2024-02-09.md": "a798d35f0b2bd1da130f7ac766166109",
    "c/types.md": "cf3e66e5aee58a94db3fdf0783908555",
-    "logic/quantification.md": "5d7579a511e9ff683edeec62bcc291b8",
+    "logic/quantification.md": "346ebe70e1fad9d95d81056ec9029793",
    "c/declarations.md": "2de27f565d1020819008ae80593af435",
    "algorithms/sorting/bubble-sort.md": "96c4b9426bcb4284de60b9144ba09b9e",
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@ -195,7 +196,7 @@
    "combinatorics/additive-principle.md": "e968028670f95ee9a7c5499ff7cb6792",
    "_journal/2024-02-19.md": "30d16c5373deb9cb128d2e7934ae256a",
    "_journal/2024-02/2024-02-18.md": "67e36dbbb2cac699d4533b5a2eaeb629",
-    "combinatorics/permutations.md": "d257cab50c2767419b0cc3f7b86bd528",
+    "combinatorics/permutations.md": "989c076a9f6909627f4decafd4118266",
    "combinatorics/combinations.md": "5ae0152180a1af7187c43606a4002202",
    "_journal/2024-02-20.md": "b85ba0eeeb16e30a602ccefabcc9763e",
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@ -207,7 +208,7 @@
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    "_journal/2024-02-23.md": "219ce9ad15a8733edd476c97628b71fd",
    "_journal/2024-02/2024-02-22.md": "312e55d57868026f6e80f7989a889c2b",
-    "c17/strings.md": "6bc3f41f111a7386b1abb2a196f1c683",
+    "c17/strings.md": "62b53cc9156eba2b565e33d07813cf50",
    "c17/index.md": "78576ee41d0185df82c59999142f4edb",
    "c17/escape-sequences.md": "ebc63c6cdfbe60bbc2708c1b0c8da8bb",
    "c17/declarations.md": "20e200f2b7abcab8f873cd080f4c9770",
@ -226,7 +227,7 @@
    "filesystems/cas.md": "34906013a2a60fe5ee0e31809b4838aa",
    "git/objects.md": "e9b98576291ca04496c2f0863f526cfa",
    "git/index.md": "83d2d95fc549d9e8436946c7bd058d15",
-    "encoding/integer.md": "e15129fc5ae9a8348c57c2d533feda41",
+    "encoding/integer.md": "ef26036d0c0d215e8b626b5db872b028",
    "_journal/2024-02-29.md": "f610f3caed659c1de3eed5f226cab508",
    "_journal/2024-02/2024-02-28.md": "7489377c014a2ff3c535d581961b5b82",
    "_journal/2024-03-01.md": "a532486279190b0c12954966cbf8c3fe",
@ -235,7 +236,7 @@
    "algebra/sequences/index.md": "d668df1467c7cc70691aeb1d9b17e39d",
    "_journal/2024-03-02.md": "08c3cae1df0079293b47e1e9556f1ce1",
    "_journal/2024-03/2024-03-01.md": "70da812300f284df72718dd32fc39322",
-    "algebra/sequences/triangular-numbers.md": "c6626d8aa86776b6ce794c3551862d5a",
+    "algebra/sequences/triangular-numbers.md": "dc3707088423708f2d55708d8b11f81f",
    "algebra/sequences/square-numbers.md": "886fb22fb8dbfffdd2cd233558ea3424",
    "_journal/2024-03-03.md": "c4977a3778ed227b768c3f9ad5512670",
    "_journal/2024-03/2024-03-02.md": "8136792b0ee6e08232e4f60c88d461d2",
@ -244,13 +245,27 @@
    "_journal/2024-03-05.md": "e9a911c19bb4c0ff451db793248cb4bb",
    "_journal/2024-03/2024-03-04.md": "4948d90a08af2cff58c629c9a2e11ee4",
    "algebra/sequences/geometric.md": "53936ec392b3b714bd4a9bdb4554b582",
-    "algebra/sequences/arithmetic.md": "80381ca0f2b3b9a1c155c597a7dea75a",
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    "_journal/2024-03-06.md": "ac7a3d764934f49b2be7aa76e402d853",
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+    "_journal/2024-03/2024-03-07.md": "58b84cabda4e875ab0c9e5317b2b6e2c",
+    "_journal/2024-03-09.md": "55cfba7bb14232007a2c4e11c839388a",
+    "_journal/2024-03-10.md": "b206d34f6fd1c9efec33a15dd146c87f",
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+    "_journal/2024-03/2024-03-08.md": "cc2df3428b965ae469904c1a21e00b8f",
+    "_journal/2024-03-11.md": "87aed4a4a842b0a277c752487f48cb4b",
+    "_journal/2024-03/2024-03-10.md": "4d3ccad4c8408e1ad7e5bea8269c0a2f",
+    "_journal/2024-03-12.md": "4ee623a47f951e94b979da93dc20eddf",
+    "_journal/2024-03/2024-03-11.md": "a70c73727b441a7714c764a59537d69c",
+    "_journal/2024-03-13.md": "2c0dd770d7eb17129aeb21fcbbe48532",
+    "_journal/2024-03/2024-03-12.md": "1b93e0b6fdc25301ec6053cfe3c7c7ba",
+    "_journal/2024-03-14.md": "1c173cab2e903aad876c5f11d49a8b20",
+    "_journal/2024-03/2024-03-13.md": "6a2ad92d0983c36acef93932bfec1758",
+    "git/references.md": "73792b2c7a0700a58336e045915ba0d4",
+    "_journal/2024-03-15.md": "879afe6bc882e494be20a284196747a5"
  },
  "fields_dict": {
    "Basic": [
--- a/notes/_journal/2024-03-15.md
+++ b/notes/_journal/2024-03-15.md
@ -0,0 +1,11 @@
+---
+title: "2024-03-15"
+---
+
+- [x] Anki Flashcards
+- [x] KoL
+- [ ] Sheet Music (10 min.)
+- [ ] Go (1 Life & Death Problem)
+- [ ] Korean (Read 1 Story)
+- [ ] Interview Prep (1 Practice Problem)
+- [x] Log Work Hours (Max 3 hours)
--- a/notes/_journal/2024-03/2024-03-08.md
+++ b/notes/_journal/2024-03/2024-03-08.md
--- a/notes/_journal/2024-03/2024-03-09.md
+++ b/notes/_journal/2024-03/2024-03-09.md
@ -0,0 +1,11 @@
+---
+title: "2024-03-09"
+---
+
+- [x] Anki Flashcards
+- [x] KoL
+- [ ] Sheet Music (10 min.)
+- [ ] Go (1 Life & Death Problem)
+- [ ] Korean (Read 1 Story)
+- [ ] Interview Prep (1 Practice Problem)
+- [ ] Log Work Hours (Max 3 hours)
--- a/notes/_journal/2024-03/2024-03-10.md
+++ b/notes/_journal/2024-03/2024-03-10.md
@ -0,0 +1,13 @@
+---
+title: "2024-03-10"
+---
+
+- [x] Anki Flashcards
+- [x] KoL
+- [ ] Sheet Music (10 min.)
+- [ ] Go (1 Life & Death Problem)
+- [ ] Korean (Read 1 Story)
+- [ ] Interview Prep (1 Practice Problem)
+- [ ] Log Work Hours (Max 3 hours)
+
+* Implemented an extendible hash map in C.
--- a/notes/_journal/2024-03/2024-03-11.md
+++ b/notes/_journal/2024-03/2024-03-11.md
@ -0,0 +1,14 @@
+---
+title: "2024-03-11"
+---
+
+- [x] Anki Flashcards
+- [x] KoL
+- [ ] Sheet Music (10 min.)
+- [ ] Go (1 Life & Death Problem)
+- [ ] Korean (Read 1 Story)
+- [ ] Interview Prep (1 Practice Problem)
+- [ ] Log Work Hours (Max 3 hours)
+
+* Got the bustub project up and running on NixOS.
+* Worked further on the extendible hash table implementation.
--- a/notes/_journal/2024-03/2024-03-12.md
+++ b/notes/_journal/2024-03/2024-03-12.md
@ -0,0 +1,11 @@
+---
+title: "2024-03-12"
+---
+
+- [x] Anki Flashcards
+- [x] KoL
+- [ ] Sheet Music (10 min.)
+- [ ] Go (1 Life & Death Problem)
+- [ ] Korean (Read 1 Story)
+- [ ] Interview Prep (1 Practice Problem)
+- [ ] Log Work Hours (Max 3 hours)
--- a/notes/_journal/2024-03/2024-03-13.md
+++ b/notes/_journal/2024-03/2024-03-13.md
@ -0,0 +1,14 @@
+---
+title: "2024-03-13"
+---
+
+- [x] Anki Flashcards
+- [x] KoL
+- [ ] Sheet Music (10 min.)
+- [ ] Go (1 Life & Death Problem)
+- [ ] Korean (Read 1 Story)
+- [ ] Interview Prep (1 Practice Problem)
+- [ ] Log Work Hours (Max 3 hours)
+
+* Read through floating point representations once in "Computer Systems: A Programmer's Perspective".
+* Reached chapter 4 in "Introduction to Algorithms".
--- a/notes/_journal/2024-03/2024-03-14.md
+++ b/notes/_journal/2024-03/2024-03-14.md
@ -0,0 +1,16 @@
+---
+title: "2024-03-14"
+---
+
+- [x] Anki Flashcards
+- [x] KoL
+- [ ] Sheet Music (10 min.)
+- [ ] Go (1 Life & Death Problem)
+- [ ] Korean (Read 1 Story)
+- [ ] Interview Prep (1 Practice Problem)
+- [x] Log Work Hours (Max 3 hours)
+
+* Continued working through floating point formats (IEEE 754). Did related practice problems.
+* Added flashcards on floating point `printf` flags.
+* Add notes on git references.
+* Implemented LRU-K replacer for database project.
--- a/notes/algebra/sequences/arithmetic.md
+++ b/notes/algebra/sequences/arithmetic.md
@ -115,8 +115,8 @@ END%%

 %%ANKI
 Basic
-The triangular numbers belong to what larger class of sequences?
-Back: Arithmetic sequences.
+Interpreted as an arithmetic sequence, what is the common ratio of the triangular numbers?
+Back: $1$
 Reference: Oscar Levin, *Discrete Mathematics: An Open Introduction*, 3rd ed., n.d., [https://discrete.openmathbooks.org/pdfs/dmoi3-tablet.pdf](https://discrete.openmathbooks.org/pdfs/dmoi3-tablet.pdf).
 <!--ID: 1709664600178-->
 END%%
--- a/notes/algebra/sequences/triangular-numbers.md
+++ b/notes/algebra/sequences/triangular-numbers.md
@ -117,8 +117,8 @@ END%%

 %%ANKI
 Basic
-Algebraically speaking, *what* is the $n$th triangular number?
-Back: $\sum_{k=1}^n k$.
+How is the $n$th triangular number written as a summation?
+Back: $\sum_{k=1}^n k$
 Reference: “Triangular Number,” in _Wikipedia_, January 13, 2024, [https://en.wikipedia.org/w/index.php?title=Triangular_number&oldid=1195279122](https://en.wikipedia.org/w/index.php?title=Triangular_number&oldid=1195279122).
 <!--ID: 1709419325914-->
 END%%
@ -212,7 +212,7 @@ END%%
 Basic
 Where in Pascal's triangle are the natural numbers embedded?
 Back: Along the second leftward diagonal:
-![[pascals-triangle.webp]]
+![[pascals-triangle.png]]
 Reference: “Triangular Number,” in _Wikipedia_, January 13, 2024, [https://en.wikipedia.org/w/index.php?title=Triangular_number&oldid=1195279122](https://en.wikipedia.org/w/index.php?title=Triangular_number&oldid=1195279122).
 <!--ID: 1709419325963-->
 END%%
@ -221,7 +221,7 @@ END%%
 Basic
 Where in Pascal's triangle are the triangular numbers embedded?
 Back: Along the third leftward diagonal:
-![[pascals-triangle.webp]]
+![[pascals-triangle.png]]
 Reference: “Triangular Number,” in _Wikipedia_, January 13, 2024, [https://en.wikipedia.org/w/index.php?title=Triangular_number&oldid=1195279122](https://en.wikipedia.org/w/index.php?title=Triangular_number&oldid=1195279122).
 <!--ID: 1709419325970-->
 END%%
--- a/notes/algorithms/order-growth.md
+++ b/notes/algorithms/order-growth.md
@ -1093,7 +1093,7 @@ END%%
 %%ANKI
 Basic
 What names are usually given to the existentially quantified identifers in $\omega(g(n))$'s definition?
-Back: $n_0$.
+Back: $n_0$
 Reference: Thomas H. Cormen et al., *Introduction to Algorithms*, 3rd ed (Cambridge, Mass: MIT Press, 2009).
 <!--ID: 1709519002380-->
 END%%
@ -1179,7 +1179,7 @@ END%%
 %%ANKI
 Basic
 What condition must $g(n)$ satisfy such that $\omega(g(n))$ is nonempty?
-Back: $g(n)$ must be asymptotically positive.
+Back: $g(n)$ must be asymptotically nonnegative.
 Reference: Thomas H. Cormen et al., *Introduction to Algorithms*, 3rd ed (Cambridge, Mass: MIT Press, 2009).
 <!--ID: 1709750359826-->
 END%%
--- a/notes/c17/strings.md
+++ b/notes/c17/strings.md
@ -333,9 +333,10 @@ Specifier | Description
 --------- | -----------
 `d`, `i`  | a decimal `signed int`
 `u`       | a decimal `unsigned int`
-`x`       | a hexadecimal `unsigned int` (lowercase)
-`X`       | a hexadecimal `unsigned int` (uppercase)
+`x`, `X`  | a hexadecimal `unsigned int`
 `o`       | an octal `unsigned int`
+`f`, `F`  | a `double` in fixed-point notation
+`e`, `E`  | a `double` in standard notation
 `s`       | a `NUL`-terminated string
 `c`       | a `char` character
 `p`       | `void*` address in an implementation-defined format
@ -452,6 +453,156 @@ Tags: printf
 <!--ID: 1707852083086-->
 END%%

+%%ANKI
+Cloze
+The {`%f`} format specifier outputs a {lowercase fixed-point `double`}.
+Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
+Tags: printf
+<!--ID: 1710450347005-->
+END%%
+
+%%ANKI
+Cloze
+The {`%F`} format specifier outputs an {uppercase fixed-point `double`}.
+Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
+Tags: printf
+<!--ID: 1710450347008-->
+END%%
+
+%%ANKI
+Basic
+What distinguishes format specifiers `%f` and `%F`?
+Back: The former outputs lowercase identifiers, the latter uppercase.
+Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
+Tags: printf
+<!--ID: 1710450347010-->
+END%%
+
+%%ANKI
+Basic
+What three special identifiers might specifier `%f` output?
+Back: `inf`, `infinity`, and `nan`
+Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
+Tags: printf
+<!--ID: 1710450347012-->
+END%%
+
+%%ANKI
+Basic
+What three special identifiers might specifier `%F` output?
+Back: `INF`, `INFINITY`, and `NAN`
+Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
+Tags: printf
+<!--ID: 1710450452444-->
+END%%
+
+%%ANKI
+Basic
+Which format specifier was probably used to yield `printf` output `inf`?
+Back: `%f`
+Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
+Tags: printf
+<!--ID: 1710450347014-->
+END%%
+
+%%ANKI
+Cloze
+{1:Fixed-point} notation is to {2:`%f`} whereas {2:standard/exponential} notation is to {1:`%e`}.
+Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
+Tags: printf
+<!--ID: 1710450347015-->
+END%%
+
+%%ANKI
+Basic
+Which format specifier was probably used to yield `printf` output `172.345000`?
+Back: `%f`
+Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
+Tags: printf
+<!--ID: 1710450347017-->
+END%%
+
+%%ANKI
+Basic
+What term describes the kind of output notation corresponding to `%f`?
+Back: Fixed-point notation.
+Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
+Tags: printf
+<!--ID: 1710450347018-->
+END%%
+
+%%ANKI
+Basic
+What distinguishes format specifiers `%e` and `%E`?
+Back: The former outputs an `e`, the latter an `E`.
+Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
+Tags: printf
+<!--ID: 1710450347020-->
+END%%
+
+%%ANKI
+Basic
+How many digits follows `e` in the output of `printf` specifier `%e`?
+Back: At least `2`.
+Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
+Tags: printf
+<!--ID: 1710450452447-->
+END%%
+
+%%ANKI
+Basic
+Which format specifier was probably used to yield `printf` output `1.723450e+02`?
+Back: `%e`
+Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
+Tags: printf
+<!--ID: 1710450347022-->
+END%%
+
+%%ANKI
+Basic
+What is the default precision of `%f`?
+Back: `6`
+Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
+Tags: printf
+<!--ID: 1710452502031-->
+END%%
+
+%%ANKI
+Basic
+What is the output of `printf("%e", 3.14)`?
+Back: `3.140000e00`
+Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
+Tags: printf
+<!--ID: 1710450347023-->
+END%%
+
+%%ANKI
+Basic
+What is the output of `printf("%e", 314)`?
+Back: `3.140000e02`
+Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
+Tags: printf
+<!--ID: 1710450347025-->
+END%%
+
+%%ANKI
+Basic
+What term describes the kind of output notation corresponding to `%e`?
+Back: Standard or exponential notation.
+Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
+Tags: printf
+<!--ID: 1710450347026-->
+END%%
+
+%%ANKI
+Basic
+What is the default precision of `%e`?
+Back: `6`
+Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
+Tags: printf
+<!--ID: 1710452502034-->
+END%%
+
 %%ANKI
 Cloze
 The {`%o`} format specifier outputs an {octal `unsigned int`}.
--- a/notes/combinatorics/images/pascals-triangle.png
+++ b/notes/combinatorics/images/pascals-triangle.png
--- a/notes/combinatorics/images/pascals-triangle.webp
+++ b/notes/combinatorics/images/pascals-triangle.webp
--- a/notes/combinatorics/permutations.md
+++ b/notes/combinatorics/permutations.md
@ -314,7 +314,7 @@ Basic
 ```
 [ a₁ a₂ ... aᵢ | aᵢ₊₁ aᵢ₊₂ ... aₙ ]
 ```
-Back: Values are in decreasing order.
+Back: Values are in non-increasing order.
 Reference: [https://leetcode.com/problems/next-permutation/description/](https://leetcode.com/problems/next-permutation/description/)
 <!--ID: 1709756610384-->
 END%%
@ -336,7 +336,7 @@ Basic
 ```
 [ a₁ a₂ ... aⱼ | aₙ ... aᵢ ... aᵢ₊₂ aᵢ₊₁ ]
 ```
-Back: Values are in decreasing order.
+Back: Values are in non-increasing order.
 Reference: [https://leetcode.com/problems/next-permutation/description/](https://leetcode.com/problems/next-permutation/description/)
 <!--ID: 1709756610399-->
 END%%
--- a/notes/encoding/integer.md
+++ b/notes/encoding/integer.md
@ -643,7 +643,7 @@ END%%

 ## Casting

-Most implementations of C cast an object of one type to another by simply re-interpreting the object's binary representation. This casting may happen implicitly if comparing or operating on e.g. `signed` and `unsigned` objects in the same expression. $T2U$ and $U2T$ reflect this method of casting:
+Most implementations of C cast an object of `signed` type to `unsigned` type and vice versa, most implementations simply re-interpret the object's binary representation. This casting may happen implicitly if comparing or operating on `signed` and `unsigned` objects in the same expression. $T2U$ and $U2T$ reflect this method of casting:

 $$T2U_w(x) = \begin{cases}
 x + 2^w & x < 0 \\
@ -657,7 +657,7 @@ x - 2^w & x > TMax_w

 %%ANKI
 Basic
-How do most implementations of C perform casting?
+How do most implementations of C perform casting of `signed` and `unsigned` types?
 Back: As a reinterpretation of the same byte pattern of the object being casted.
 Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
 Tags: c17
@ -1714,7 +1714,7 @@ END%%
 %%ANKI
 Basic
 What pre-processing step is done when multiplying to a $w$-bit two's-complement result by hand?
-Back: Sign extend the factors to width $w$.
+Back: Sign extend the factors to width $2w$.
 Reference: “Two’s-Complement.” In *Wikipedia*, January 9, 2024. [https://en.wikipedia.org/w/index.php?title=Two%27s_complement&oldid=1194543561](https://en.wikipedia.org/w/index.php?title=Two%27s_complement&oldid=1194543561).
 <!--ID: 1709563221449-->
 END%%
--- a/notes/git/references.md
+++ b/notes/git/references.md
@ -0,0 +1,197 @@
+---
+title: References
+TARGET DECK: Obsidian::STEM
+FILE TAGS: git
+tags:
+  - git
+---
+
+## Overview
+
+A **reference** is essentially a file containing an oid. The name of the file can then be used to reference the oid. A **symbolic reference** is a file containing the name of another reference.
+
+%%ANKI
+Basic
+What is a git ref?
+Back: A user-friendly name for referring to some git object.
+Reference: Scott Chacon, *Pro Git*, Second edition, The Expert’s Voice in Software Development (New York, NY: Apress, 2014).
+<!--ID: 1710454031260-->
+END%%
+
+%%ANKI
+Basic
+How is a git ref realized on disk?
+Back: It is a file containing an oid.
+Reference: Scott Chacon, *Pro Git*, Second edition, The Expert’s Voice in Software Development (New York, NY: Apress, 2014).
+<!--ID: 1710454031263-->
+END%%
+
+%%ANKI
+Basic
+What shorter terminology refers to "git references"?
+Back: Git refs.
+Reference: Scott Chacon, *Pro Git*, Second edition, The Expert’s Voice in Software Development (New York, NY: Apress, 2014).
+<!--ID: 1710454031266-->
+END%%
+
+%%ANKI
+Basic
+Where on disk are git refs stored?
+Back: In the `.git/refs` directory.
+Reference: Scott Chacon, *Pro Git*, Second edition, The Expert’s Voice in Software Development (New York, NY: Apress, 2014).
+<!--ID: 1710454031269-->
+END%%
+
+%%ANKI
+Basic
+Where on disk are git local branch refs stored?
+Back: `.git/refs/heads`
+Reference: Scott Chacon, *Pro Git*, Second edition, The Expert’s Voice in Software Development (New York, NY: Apress, 2014).
+<!--ID: 1710454031271-->
+END%%
+
+%%ANKI
+Basic
+Where on disk are git remote branch refs stored?
+Back: `.git/refs/remotes`
+Reference: Scott Chacon, *Pro Git*, Second edition, The Expert’s Voice in Software Development (New York, NY: Apress, 2014).
+<!--ID: 1710454031273-->
+END%%
+
+%%ANKI
+Cloze
+The {`update-ref`} plumbing command is used to manage {reference files}.
+Reference: Scott Chacon, *Pro Git*, Second edition, The Expert’s Voice in Software Development (New York, NY: Apress, 2014).
+<!--ID: 1710454031275-->
+END%%
+
+%%ANKI
+Basic
+Why is the `update-ref` command's name a slight misnomer?
+Back: It is also used to create references.
+Reference: Scott Chacon, *Pro Git*, Second edition, The Expert’s Voice in Software Development (New York, NY: Apress, 2014).
+<!--ID: 1710454031277-->
+END%%
+
+%%ANKI
+Basic
+What plumbing command is used in favor of manually editing reference files?
+Back: `update-ref`
+Reference: Scott Chacon, *Pro Git*, Second edition, The Expert’s Voice in Software Development (New York, NY: Apress, 2014).
+<!--ID: 1710454031279-->
+END%%
+
+%%ANKI
+Basic
+How do I complete the following command to update `master` to the new oid?
+```bash
+$ git update-ref ___ 1a410efbd13591db07496601ebc7a059dd55cfe9
+```
+Back: `refs/heads/master`
+Reference: Scott Chacon, *Pro Git*, Second edition, The Expert’s Voice in Software Development (New York, NY: Apress, 2014).
+<!--ID: 1710454031281-->
+END%%
+
+%%ANKI
+Basic
+Git (basically) invokes what plumbing command on new branch creation?
+Back: `update-ref`
+Reference: Scott Chacon, *Pro Git*, Second edition, The Expert’s Voice in Software Development (New York, NY: Apress, 2014).
+<!--ID: 1710454031283-->
+END%%
+
+%%ANKI
+Basic
+What is a git symbolic ref?
+Back: A git ref that points to another ref (as opposed to an oid).
+Reference: Scott Chacon, *Pro Git*, Second edition, The Expert’s Voice in Software Development (New York, NY: Apress, 2014).
+<!--ID: 1710454758061-->
+END%%
+
+%%ANKI
+Basic
+Which symbolic ref is most commonly used?
+Back: `HEAD`
+Reference: Scott Chacon, *Pro Git*, Second edition, The Expert’s Voice in Software Development (New York, NY: Apress, 2014).
+<!--ID: 1710454758064-->
+END%%
+
+%%ANKI
+Basic
+What does it mean to be in "detached head state"?
+Back: `HEAD` refers to an oid instead of another ref.
+Reference: Scott Chacon, *Pro Git*, Second edition, The Expert’s Voice in Software Development (New York, NY: Apress, 2014).
+<!--ID: 1710454758066-->
+END%%
+
+%%ANKI
+Basic
+What term describes when `HEAD` is a normal ref instead of a symbolic ref?
+Back: Detached head state.
+Reference: Scott Chacon, *Pro Git*, Second edition, The Expert’s Voice in Software Development (New York, NY: Apress, 2014).
+<!--ID: 1710454758068-->
+END%%
+
+%%ANKI
+Basic
+Where on disk is `HEAD` normally located?
+Back: `.git/HEAD`
+Reference: Scott Chacon, *Pro Git*, Second edition, The Expert’s Voice in Software Development (New York, NY: Apress, 2014).
+<!--ID: 1710454758070-->
+END%%
+
+%%ANKI
+Basic
+What does the contents of `.git/HEAD` normally look like?
+Back: `ref: refs/heads/<BRANCH>`
+Reference: Scott Chacon, *Pro Git*, Second edition, The Expert’s Voice in Software Development (New York, NY: Apress, 2014).
+<!--ID: 1710454758071-->
+END%%
+
+%%ANKI
+Basic
+What does the contents of `.git/HEAD` look like in detached head state?
+Back: `<OID>`
+Reference: Scott Chacon, *Pro Git*, Second edition, The Expert’s Voice in Software Development (New York, NY: Apress, 2014).
+<!--ID: 1710454758073-->
+END%%
+
+%%ANKI
+Basic
+What plumbing command is used in favor of manually editing symbolic reference files?
+Back: `symbolic-ref`
+Reference: Scott Chacon, *Pro Git*, Second edition, The Expert’s Voice in Software Development (New York, NY: Apress, 2014).
+<!--ID: 1710454758074-->
+END%%
+
+%%ANKI
+Cloze
+Normal refs are to {`update-ref`} whereas symbolic refs are to {`symbolic-ref`}.
+Reference: Scott Chacon, *Pro Git*, Second edition, The Expert’s Voice in Software Development (New York, NY: Apress, 2014).
+<!--ID: 1710454758076-->
+END%%
+
+%%ANKI
+Cloze
+The {`symbolic-ref`} plumbing command is used to manage {symbolic reference files}.
+Reference: Scott Chacon, *Pro Git*, Second edition, The Expert’s Voice in Software Development (New York, NY: Apress, 2014).
+<!--ID: 1710454758077-->
+END%%
+
+%%ANKI
+Basic
+How do you correctly write the following command?
+```bash
+$ git symbolic-ref HEAD test
+```
+Back:
+```bash
+$ git symbolic-ref HEAD refs/heads/test
+```
+Reference: Scott Chacon, *Pro Git*, Second edition, The Expert’s Voice in Software Development (New York, NY: Apress, 2014).
+<!--ID: 1710454758079-->
+END%%
+
+## References
+
+* Scott Chacon, *Pro Git*, Second edition, The Expert’s Voice in Software Development (New York, NY: Apress, 2014).
--- a/notes/logic/quantification.md
+++ b/notes/logic/quantification.md
@ -39,7 +39,7 @@ END%%

 %%ANKI
 Basic
-How many members must satisfy a property in existential quantification?
+How many members in the domain of discourse must satisfy a property in existential quantification?
 Back: At least one.
 Reference: Gries, David. *The Science of Programming*. Texts and Monographs in Computer Science. New York: Springer-Verlag, 1981.
 <!--ID: 1707494819967-->
@ -81,7 +81,7 @@ END%%

 %%ANKI
 Basic
-How many members must satisfy a property in universal quantification?
+How many members in the domain of discourse must satisfy a property in universal quantification?
 Back: All of them.
 Reference: Gries, David. *The Science of Programming*. Texts and Monographs in Computer Science. New York: Springer-Verlag, 1981.
 <!--ID: 1707494819973-->