diff --git a/notes/.obsidian/plugins/obsidian-to-anki-plugin/data.json b/notes/.obsidian/plugins/obsidian-to-anki-plugin/data.json index 639e739..b2c704e 100644 --- a/notes/.obsidian/plugins/obsidian-to-anki-plugin/data.json +++ b/notes/.obsidian/plugins/obsidian-to-anki-plugin/data.json @@ -755,7 +755,7 @@ "_journal/2024-08-19.md": "94836e52ec04a72d3e1dbf3854208f65", "_journal/2024-08/2024-08-18.md": "6f8aec69e00401b611db2a377a3aace5", "_journal/2024-08/2024-08-17.md": "b06a551560c377f61a1b39286cd43cee", - "calculus/bounds.md": "4add5fb7591087d0b3383c53dc62e365", + "calculus/bounds.md": "b410b7bc5beb5db799fe32b319745bb9", "calculus/index.md": "5ee4d950533ae330ca5ef9e113fe87f3", "x86-64/instructions/conditions.md": "c5571deac40ac2eeb8666f2d3b3c278e", "_journal/2024-08-20.md": "e8bec308d1b29e411c6799ace7ef6571", @@ -767,7 +767,7 @@ "_journal/2024-08/2024-08-20.md": "e8bec308d1b29e411c6799ace7ef6571", "_journal/2024-08-23.md": "3b2feab2cc927e267263cb1e9c173d50", "set/natural-numbers.md": "97ca466daf1173ed8973db1d1a1935cc", - "_journal/2024-08-24.md": "15ad542d09725f672765f9915deb66bd", + "_journal/2024-08-24.md": "563fad24740e44734a87d7c3ec46cec4", "_journal/2024-08/2024-08-23.md": "7b5a40e83d8f07ff54cd9708017d029c", "_journal/2024-08/2024-08-22.md": "050235d5dc772b542773743b57ce3afe" }, diff --git a/notes/_journal/2024-08-24.md b/notes/_journal/2024-08-24.md index ad7a89b..c6b3ec1 100644 --- a/notes/_journal/2024-08-24.md +++ b/notes/_journal/2024-08-24.md @@ -8,4 +8,5 @@ title: "2024-08-24" - [ ] Sheet Music (10 min.) - [ ] Korean (Read 1 Story) -* Began notes on [[natural-numbers|natural numbers]]. \ No newline at end of file +* Began notes on [[natural-numbers|natural numbers]]. +* Additional notes on supremums and infimums. \ No newline at end of file diff --git a/notes/calculus/bounds.md b/notes/calculus/bounds.md index 7d6aa6f..47d42bf 100644 --- a/notes/calculus/bounds.md +++ b/notes/calculus/bounds.md @@ -264,6 +264,110 @@ Reference: Tom M. Apostol, _Calculus, Vol. 1: One-Variable Calculus, with an Int END%% +%%ANKI +Basic +Let $S \subseteq \mathbb{R}$ have a supremum. If $h > 0$, *why* does there exist an $x \in S$ such that $x > \mathop{\text{sup}} S - h$? +Back: Otherwise $\mathop{\text{sup}}S - h$ is an upper bound less than $\mathop{\text{sup}}S$. +Reference: Tom M. Apostol, _Calculus, Vol. 1: One-Variable Calculus, with an Introduction to Linear Algebra_, 2nd ed. (New York: Wiley, 1980). + +END%% + +%%ANKI +Basic +Let $S \subseteq \mathbb{R}$ have a supremum. If $h > 0$, *why* does there exist an $x \in S$ such that $x < \mathop{\text{sup}} S - h$? +Back: N/A. This is not necessarily the case. +Reference: Tom M. Apostol, _Calculus, Vol. 1: One-Variable Calculus, with an Introduction to Linear Algebra_, 2nd ed. (New York: Wiley, 1980). + +END%% + +%%ANKI +Basic +Let $S \subseteq \mathbb{R}$ have an infimum. If $h > 0$, *why* does there exist an $x \in S$ such that $x > \mathop{\text{inf}} S + h$? +Back: N/A. This is not necessarily the case. +Reference: Tom M. Apostol, _Calculus, Vol. 1: One-Variable Calculus, with an Introduction to Linear Algebra_, 2nd ed. (New York: Wiley, 1980). + +END%% + +%%ANKI +Basic +Let $S \subseteq \mathbb{R}$ have an infimum. If $h > 0$, *why* does there exist an $x \in S$ such that $x < \mathop{\text{inf}} S + h$? +Back: Otherwise $\mathop{\text{inf}}S + h$ is a lower bound greater than $\mathop{\text{inf}}S$. +Reference: Tom M. Apostol, _Calculus, Vol. 1: One-Variable Calculus, with an Introduction to Linear Algebra_, 2nd ed. (New York: Wiley, 1980). + +END%% + +%%ANKI +Basic +Let $A, B \subseteq \mathbb{R}$ have supremums. What set $C$ satisfies $\mathop{\text{sup}}C = \mathop{\text{sup}}A + \mathop{\text{sup}}B$? +Back: $C = \{a + b \mid a \in A, b \in B\}$ +Reference: Tom M. Apostol, _Calculus, Vol. 1: One-Variable Calculus, with an Introduction to Linear Algebra_, 2nd ed. (New York: Wiley, 1980). + +END%% + +%%ANKI +Basic +Let $A, B \subseteq \mathbb{R}$. When is $\mathop{\text{sup}} \,\{a + b \mid a \in A, b \in B\}$ defined? +Back: When $A$ and $B$ both have a supremum. +Reference: Tom M. Apostol, _Calculus, Vol. 1: One-Variable Calculus, with an Introduction to Linear Algebra_, 2nd ed. (New York: Wiley, 1980). + +END%% + +%%ANKI +Basic +Let $A, B \subseteq \mathbb{R}$. When is $\mathop{\text{inf}} \,\{a + b \mid a \in A, b \in B\}$ defined? +Back: When $A$ and $B$ both have an infimum. +Reference: Tom M. Apostol, _Calculus, Vol. 1: One-Variable Calculus, with an Introduction to Linear Algebra_, 2nd ed. (New York: Wiley, 1980). + +END%% + +%%ANKI +Basic +Let $A, B \subseteq \mathbb{R}$ have infimums. What set $C$ satisfies $\mathop{\text{inf}}C = \mathop{\text{inf}}A + \mathop{\text{inf}}B$? +Back: $C = \{a + b \mid a \in A, b \in B\}$ +Reference: Tom M. Apostol, _Calculus, Vol. 1: One-Variable Calculus, with an Introduction to Linear Algebra_, 2nd ed. (New York: Wiley, 1980). + +END%% + +%%ANKI +Basic +Let $S, T \subseteq \mathbb{R}$ be nonempty sets such that $\forall s \in S, \forall t \in T, s \leq t$. Does $S$ have a supremum? +Back: Yes. +Reference: Tom M. Apostol, _Calculus, Vol. 1: One-Variable Calculus, with an Introduction to Linear Algebra_, 2nd ed. (New York: Wiley, 1980). + +END%% + +%%ANKI +Basic +Let $S, T \subseteq \mathbb{R}$ be nonempty sets such that $\forall s \in S, \forall t \in T, s \leq t$. Does $T$ have a supremum? +Back: Indeterminate. +Reference: Tom M. Apostol, _Calculus, Vol. 1: One-Variable Calculus, with an Introduction to Linear Algebra_, 2nd ed. (New York: Wiley, 1980). + +END%% + +%%ANKI +Basic +Let $S, T \subseteq \mathbb{R}$ be nonempty sets such that $\forall s \in S, \forall t \in T, s \leq t$. Does $S$ have an infimum? +Back: Indeterminate. +Reference: Tom M. Apostol, _Calculus, Vol. 1: One-Variable Calculus, with an Introduction to Linear Algebra_, 2nd ed. (New York: Wiley, 1980). + +END%% + +%%ANKI +Basic +Let $S, T \subseteq \mathbb{R}$ be nonempty sets such that $\forall s \in S, \forall t \in T, s \leq t$. Does $T$ have an infimum? +Back: Yes. +Reference: Tom M. Apostol, _Calculus, Vol. 1: One-Variable Calculus, with an Introduction to Linear Algebra_, 2nd ed. (New York: Wiley, 1980). + +END%% + +%%ANKI +Basic +Let $S, T \subseteq \mathbb{R}$ be nonempty sets such that $\forall s \in S, \forall t \in T, s \leq t$. How does $\mathop{\text{sup}} S$ compare to $\mathop{\text{inf}} T$? +Back: $\mathop{\text{sup}}S \leq \mathop{\text{inf}}T$ +Reference: Tom M. Apostol, _Calculus, Vol. 1: One-Variable Calculus, with an Introduction to Linear Algebra_, 2nd ed. (New York: Wiley, 1980). + +END%% + ### Completeness Axiom Every nonempty set $S$ of real numbers which is bounded above has a supremum; that is, there is a real number $B$ such that $B = \mathop{\text{sup}} S$.