Remove no longer needed `hyperlabel` command.

finite-set-exercises
Joshua Potter 2023-05-10 20:27:46 -06:00
parent 53a0bd1ebc
commit 50d6b13574
8 changed files with 47 additions and 50 deletions

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@ -18,12 +18,12 @@ The properties of area in this set of exercises are to be deduced from the
axioms for area stated in the foregoing section. axioms for area stated in the foregoing section.
\section*{Exercise 1}% \section*{Exercise 1}%
\hyperlabel{sec:exercise-1}% \label{sec:exercise-1}
Prove that each of the following sets is measurable and has zero area: Prove that each of the following sets is measurable and has zero area:
\subsection*{\proceeding{Exercise 1a}}% \subsection*{\proceeding{Exercise 1a}}%
\hyperlabel{sub:exercise-1a}% \label{sub:exercise-1a}
A set consisting of a single point. A set consisting of a single point.
@ -39,7 +39,7 @@ A set consisting of a single point.
\end{proof} \end{proof}
\subsection*{\proceeding{Exercise 1b}}% \subsection*{\proceeding{Exercise 1b}}%
\hyperlabel{sub:exercise-1b}% \label{sub:exercise-1b}
A set consisting of a finite number of points in a plane. A set consisting of a finite number of points in a plane.
@ -98,7 +98,7 @@ A set consisting of a finite number of points in a plane.
\end{proof} \end{proof}
\subsection*{\proceeding{Exercise 1c}}% \subsection*{\proceeding{Exercise 1c}}%
\hyperlabel{sub:exercise-1c}% \label{sub:exercise-1c}
The union of a finite collection of line segments in a plane. The union of a finite collection of line segments in a plane.
@ -161,7 +161,7 @@ The union of a finite collection of line segments in a plane.
\end{proof} \end{proof}
\section*{\unverified{Exercise 2}}% \section*{\unverified{Exercise 2}}%
\hyperlabel{sec:exercise-2}% \label{sec:exercise-2}
Every right triangular region is measurable because it can be obtained as the Every right triangular region is measurable because it can be obtained as the
intersection of two rectangles. intersection of two rectangles.
@ -212,7 +212,7 @@ Prove that every triangular region is measurable and that its area is one half
\end{proof} \end{proof}
\section*{\unverified{Exercise 3}}% \section*{\unverified{Exercise 3}}%
\hyperlabel{sec:exercise-3}% \label{sec:exercise-3}
Prove that every trapezoid and every parallelogram is measurable and derive the Prove that every trapezoid and every parallelogram is measurable and derive the
usual formulas for their areas. usual formulas for their areas.
@ -319,14 +319,14 @@ Prove that every trapezoid and every parallelogram is measurable and derive the
\end{proof} \end{proof}
\section*{Exercise 4}% \section*{Exercise 4}%
\hyperlabel{sec:exercise-4}% \label{sec:exercise-4}
Let $P$ be a polygon whose vertices are lattice points. Let $P$ be a polygon whose vertices are lattice points.
The area of $P$ is $I + \frac{1}{2}B - 1$, where $I$ denotes the number of The area of $P$ is $I + \frac{1}{2}B - 1$, where $I$ denotes the number of
lattice points inside the polygon and $B$ denotes the number on the boundary. lattice points inside the polygon and $B$ denotes the number on the boundary.
\subsection*{\unverified{Exercise 4a}}% \subsection*{\unverified{Exercise 4a}}%
\hyperlabel{sub:exercise-4a}% \label{sub:exercise-4a}
Prove that the formula is valid for rectangles with sides parallel to the Prove that the formula is valid for rectangles with sides parallel to the
coordinate axes. coordinate axes.
@ -354,7 +354,7 @@ Prove that the formula is valid for rectangles with sides parallel to the
\end{proof} \end{proof}
\subsection*{\unverified{Exercise 4b}}% \subsection*{\unverified{Exercise 4b}}%
\hyperlabel{sub:exercise-4b}% \label{sub:exercise-4b}
Prove that the formula is valid for right triangles and parallelograms. Prove that the formula is valid for right triangles and parallelograms.
@ -408,7 +408,7 @@ Prove that the formula is valid for right triangles and parallelograms.
\end{proof} \end{proof}
\subsection*{\unverified{Exercise 4c}}% \subsection*{\unverified{Exercise 4c}}%
\hyperlabel{sub:exercise-4c}% \label{sub:exercise-4c}
Use induction on the number of edges to construct a proof for general polygons. Use induction on the number of edges to construct a proof for general polygons.
@ -474,7 +474,7 @@ Use induction on the number of edges to construct a proof for general polygons.
\end{proof} \end{proof}
\section*{\unverified{Exercise 5}}% \section*{\unverified{Exercise 5}}%
\hyperlabel{sec:exercise-5}% \label{sec:exercise-5}
Prove that a triangle whose vertices are lattice points cannot be equilateral. Prove that a triangle whose vertices are lattice points cannot be equilateral.
@ -510,7 +510,7 @@ ways, using Exercises 2 and 4.]
\end{proof} \end{proof}
\section*{\unverified{Exercise 6}}% \section*{\unverified{Exercise 6}}%
\hyperlabel{sec:exercise-6}% \label{sec:exercise-6}
Let $A = \{1, 2, 3, 4, 5\}$, and let $\mathscr{M}$ denote the class of all Let $A = \{1, 2, 3, 4, 5\}$, and let $\mathscr{M}$ denote the class of all
subsets of $A$. subsets of $A$.

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@ -11,12 +11,12 @@
\header{Exercises 1.11}{Tom M. Apostol} \header{Exercises 1.11}{Tom M. Apostol}
\section*{Exercise 4}% \section*{Exercise 4}%
\hyperlabel{sec:exercise-4}% \label{sec:exercise-4}
Prove that the greatest-integer function has the properties indicated: Prove that the greatest-integer function has the properties indicated:
\subsection*{\proceeding{Exercise 4a}}% \subsection*{\proceeding{Exercise 4a}}%
\hyperlabel{sub:exercise-4a}% \label{sub:exercise-4a}
$\floor{x + n} = \floor{x} + n$ for every integer $n$. $\floor{x + n} = \floor{x} + n$ for every integer $n$.
@ -27,7 +27,7 @@ $\floor{x + n} = \floor{x} + n$ for every integer $n$.
\end{proof} \end{proof}
\subsection*{\proceeding{Exercise 4b}}% \subsection*{\proceeding{Exercise 4b}}%
\hyperlabel{sub:exercise-4b}% \label{sub:exercise-4b}
$\floor{-x} = $\floor{-x} =
\begin{cases} \begin{cases}
@ -47,7 +47,7 @@ $\floor{-x} =
\end{proof} \end{proof}
\subsection*{\proceeding{Exercise 4c}}% \subsection*{\proceeding{Exercise 4c}}%
\hyperlabel{sub:exercise-4c}% \label{sub:exercise-4c}
$\floor{x + y} = \floor{x} + \floor{y}$ or $\floor{x} + \floor{y} + 1$. $\floor{x + y} = \floor{x} + \floor{y}$ or $\floor{x} + \floor{y} + 1$.
@ -58,7 +58,7 @@ $\floor{x + y} = \floor{x} + \floor{y}$ or $\floor{x} + \floor{y} + 1$.
\end{proof} \end{proof}
\subsection*{\proceeding{Exercise 4d}}% \subsection*{\proceeding{Exercise 4d}}%
\hyperlabel{sub:exercise-4d}% \label{sub:exercise-4d}
$\floor{2x} = \floor{x} + \floor{x + \frac{1}{2}}.$ $\floor{2x} = \floor{x} + \floor{x + \frac{1}{2}}.$
@ -69,7 +69,7 @@ $\floor{2x} = \floor{x} + \floor{x + \frac{1}{2}}.$
\end{proof} \end{proof}
\subsection*{\proceeding{Exercise 4e}}% \subsection*{\proceeding{Exercise 4e}}%
\hyperlabel{sub:exercise-4e}% \label{sub:exercise-4e}
$\floor{3x} = \floor{x} + \floor{x + \frac{1}{3}} + \floor{x + \frac{2}{3}}.$ $\floor{3x} = \floor{x} + \floor{x + \frac{1}{3}} + \floor{x + \frac{2}{3}}.$
@ -80,7 +80,7 @@ $\floor{3x} = \floor{x} + \floor{x + \frac{1}{3}} + \floor{x + \frac{2}{3}}.$
\end{proof} \end{proof}
\section*{\proceeding{Exercise 5}}% \section*{\proceeding{Exercise 5}}%
\hyperlabel{sec:exercise-5}% \label{sec:exercise-5}
The formulas in Exercises 4(d) and 4(e) suggest a generalization for The formulas in Exercises 4(d) and 4(e) suggest a generalization for
$\floor{nx}$. $\floor{nx}$.
@ -169,7 +169,7 @@ State and prove such a generalization.
\end{proof} \end{proof}
\section*{\unverified{Exercise 6}}% \section*{\unverified{Exercise 6}}%
\hyperlabel{sec:exercise-6}% \label{sec:exercise-6}
Recall that a lattice point $(x, y)$ in the plane is one whose coordinates are Recall that a lattice point $(x, y)$ in the plane is one whose coordinates are
integers. integers.
@ -193,14 +193,14 @@ Prove that the number of lattice points in $S$ is equal to the sum
\end{proof} \end{proof}
\section*{Exercise 7}% \section*{Exercise 7}%
\hyperlabel{sec:exercise-7}% \label{sec:exercise-7}
If $a$ and $b$ are positive integers with no common factor, we have the formula If $a$ and $b$ are positive integers with no common factor, we have the formula
$$\sum_{n=1}^{b-1} \floor{\frac{na}{b}} = \frac{(a - 1)(b - 1)}{2}.$$ $$\sum_{n=1}^{b-1} \floor{\frac{na}{b}} = \frac{(a - 1)(b - 1)}{2}.$$
When $b = 1$, the sum on the left is understood to be $0$. When $b = 1$, the sum on the left is understood to be $0$.
\subsection*{\unverified{Exercise 7a}}% \subsection*{\unverified{Exercise 7a}}%
\hyperlabel{sub:exercise-7a}% \label{sub:exercise-7a}
Derive this result by a geometric argument, counting lattice points in a right Derive this result by a geometric argument, counting lattice points in a right
triangle. triangle.
@ -212,7 +212,7 @@ Derive this result by a geometric argument, counting lattice points in a right
\end{proof} \end{proof}
\subsection*{\proceeding{Exercise 7b}}% \subsection*{\proceeding{Exercise 7b}}%
\hyperlabel{sub:exercise-7b}% \label{sub:exercise-7b}
Derive the result analytically as follows: Derive the result analytically as follows:
By changing the index of summation, note that By changing the index of summation, note that
@ -226,7 +226,7 @@ Now apply Exercises 4(a) and (b) to the bracket on the right.
\end{proof} \end{proof}
\section*{\unverified{Exercise 8}}% \section*{\unverified{Exercise 8}}%
\hyperlabel{sec:exercise-8}% \label{sec:exercise-8}
Let $S$ be a set of points on the real line. Let $S$ be a set of points on the real line.
The \textit{characteristic function} of $S$ is, by definition, the function The \textit{characteristic function} of $S$ is, by definition, the function

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@ -11,7 +11,7 @@
\header{A Set of Axioms for the Real-Number System}{Tom M. Apostol} \header{A Set of Axioms for the Real-Number System}{Tom M. Apostol}
\section*{\verified{Lemma 1}}% \section*{\verified{Lemma 1}}%
\hyperlabel{sec:lemma-1}% \label{sec:lemma-1}
Nonempty set $S$ has supremum $L$ if and only if set $-S$ has infimum $-L$. Nonempty set $S$ has supremum $L$ if and only if set $-S$ has infimum $-L$.
@ -31,7 +31,7 @@ Nonempty set $S$ has supremum $L$ if and only if set $-S$ has infimum $-L$.
\end{proof} \end{proof}
\section*{\verified{Theorem I.27}}% \section*{\verified{Theorem I.27}}%
\hyperlabel{sec:theorem-i.27}% \label{sec:theorem-i.27}
Every nonempty set $S$ that is bounded below has a greatest lower bound; that Every nonempty set $S$ that is bounded below has a greatest lower bound; that
is, there is a real number $L$ such that $L = \inf{S}$. is, there is a real number $L$ such that $L = \inf{S}$.
@ -51,7 +51,7 @@ Every nonempty set $S$ that is bounded below has a greatest lower bound; that
\end{proof} \end{proof}
\section*{\verified{Theorem I.29}}% \section*{\verified{Theorem I.29}}%
\hyperlabel{sec:theorem-i.29} \label{sec:theorem-i.29}
For every real $x$ there exists a positive integer $n$ such that $n > x$. For every real $x$ there exists a positive integer $n$ such that $n > x$.
@ -71,7 +71,7 @@ For every real $x$ there exists a positive integer $n$ such that $n > x$.
\end{proof} \end{proof}
\section*{\verified{Theorem I.30}}% \section*{\verified{Theorem I.30}}%
\hyperlabel{sec:theorem-i.30}% \label{sec:theorem-i.30}
If $x > 0$ and if $y$ is an arbitrary real number, there exists a positive If $x > 0$ and if $y$ is an arbitrary real number, there exists a positive
integer $n$ such that $nx > y$. integer $n$ such that $nx > y$.
@ -92,7 +92,7 @@ If $x > 0$ and if $y$ is an arbitrary real number, there exists a positive
\end{proof} \end{proof}
\section*{\verified{Theorem I.31}}% \section*{\verified{Theorem I.31}}%
\hyperlabel{sec:theorem-i.31}% \label{sec:theorem-i.31}
If three real numbers $a$, $x$, and $y$ satisfy the inequalities If three real numbers $a$, $x$, and $y$ satisfy the inequalities
$$a \leq x \leq a + \frac{y}{n}$$ for every integer $n \geq 1$, then $x = a$. $$a \leq x \leq a + \frac{y}{n}$$ for every integer $n \geq 1$, then $x = a$.
@ -135,7 +135,7 @@ If three real numbers $a$, $x$, and $y$ satisfy the inequalities
\end{proof} \end{proof}
\section*{\verified{Lemma 2}}% \section*{\verified{Lemma 2}}%
\hyperlabel{sec:lemma-2}% \label{sec:lemma-2}
If three real numbers $a$, $x$, and $y$ satisfy the inequalities If three real numbers $a$, $x$, and $y$ satisfy the inequalities
$$a - y / n \leq x \leq a$$ for every integer $n \geq 1$, then $x = a$. $$a - y / n \leq x \leq a$$ for every integer $n \geq 1$, then $x = a$.
@ -178,12 +178,12 @@ If three real numbers $a$, $x$, and $y$ satisfy the inequalities
\end{proof} \end{proof}
\section*{Theorem I.32}% \section*{Theorem I.32}%
\hyperlabel{sec:theorem-i.32}% \label{sec:theorem-i.32}
Let $h$ be a given positive number and let $S$ be a set of real numbers. Let $h$ be a given positive number and let $S$ be a set of real numbers.
\subsection*{\verified{Theorem I.32a}}% \subsection*{\verified{Theorem I.32a}}%
\hyperlabel{sub:theorem-i.32a}% \label{sub:theorem-i.32a}
If $S$ has a supremum, then for some $x$ in $S$ we have $x > \sup{S} - h$. If $S$ has a supremum, then for some $x$ in $S$ we have $x > \sup{S} - h$.
@ -205,7 +205,7 @@ If $S$ has a supremum, then for some $x$ in $S$ we have $x > \sup{S} - h$.
\end{proof} \end{proof}
\subsection*{\verified{Theorem I.32b}}% \subsection*{\verified{Theorem I.32b}}%
\hyperlabel{sub:theorem-i.32b}% \label{sub:theorem-i.32b}
If $S$ has an infimum, then for some $x$ in $S$ we have $x < \inf{S} + h$. If $S$ has an infimum, then for some $x$ in $S$ we have $x < \inf{S} + h$.
@ -227,7 +227,7 @@ If $S$ has an infimum, then for some $x$ in $S$ we have $x < \inf{S} + h$.
\end{proof} \end{proof}
\section*{Theorem I.33}% \section*{Theorem I.33}%
\hyperlabel{sec:theorem-i.33}% \label{sec:theorem-i.33}
Given nonempty subsets $A$ and $B$ of $\mathbb{R}$, let $C$ denote the set Given nonempty subsets $A$ and $B$ of $\mathbb{R}$, let $C$ denote the set
$$C = \{a + b : a \in A, b \in B\}.$$ $$C = \{a + b : a \in A, b \in B\}.$$
@ -235,7 +235,7 @@ Given nonempty subsets $A$ and $B$ of $\mathbb{R}$, let $C$ denote the set
\note{This is known as the "Additive Property."} \note{This is known as the "Additive Property."}
\subsection*{\verified{Theorem I.33a}}% \subsection*{\verified{Theorem I.33a}}%
\hyperlabel{sub:theorem-i.33a}% \label{sub:theorem-i.33a}
If each of $A$ and $B$ has a supremum, then $C$ has a supremum, and If each of $A$ and $B$ has a supremum, then $C$ has a supremum, and
$$\sup{C} = \sup{A} + \sup{B}.$$ $$\sup{C} = \sup{A} + \sup{B}.$$
@ -250,7 +250,7 @@ If each of $A$ and $B$ has a supremum, then $C$ has a supremum, and
$\sup{A} + \sup{B}$ is the \textit{least} upper bound of $C$. $\sup{A} + \sup{B}$ is the \textit{least} upper bound of $C$.
\paragraph{(i)}% \paragraph{(i)}%
\hyperlabel{par:theorem-i.33a-i}% \label{par:theorem-i.33a-i}
Let $x \in C$. Let $x \in C$.
By definition of $C$, there exist elements $a' \in A$ and $b' \in B$ such By definition of $C$, there exist elements $a' \in A$ and $b' \in B$ such
@ -303,7 +303,7 @@ If each of $A$ and $B$ has a supremum, then $C$ has a supremum, and
\end{proof} \end{proof}
\subsection*{\verified{Theorem I.33b}}% \subsection*{\verified{Theorem I.33b}}%
\hyperlabel{sub:theorem-i.33b}% \label{sub:theorem-i.33b}
If each of $A$ and $B$ has an infimum, then $C$ has an infimum, and If each of $A$ and $B$ has an infimum, then $C$ has an infimum, and
$$\inf{C} = \inf{A} + \inf{B}.$$ $$\inf{C} = \inf{A} + \inf{B}.$$
@ -318,7 +318,7 @@ If each of $A$ and $B$ has an infimum, then $C$ has an infimum, and
$\inf{A} + \inf{B}$ is the \textit{greatest} lower bound of $C$. $\inf{A} + \inf{B}$ is the \textit{greatest} lower bound of $C$.
\paragraph{(i)}% \paragraph{(i)}%
\hyperlabel{par:theorem-i.33b-i}% \label{par:theorem-i.33b-i}
Let $x \in C$. Let $x \in C$.
By definition of $C$, there exist elements $a' \in A$ and $b' \in B$ such By definition of $C$, there exist elements $a' \in A$ and $b' \in B$ such
@ -371,7 +371,7 @@ If each of $A$ and $B$ has an infimum, then $C$ has an infimum, and
\end{proof} \end{proof}
\section*{\verified{Theorem I.34}}% \section*{\verified{Theorem I.34}}%
\hyperlabel{sec:theorem-i.34}% \label{sec:theorem-i.34}
Given two nonempty subsets $S$ and $T$ of $\mathbb{R}$ such that $$s \leq t$$ Given two nonempty subsets $S$ and $T$ of $\mathbb{R}$ such that $$s \leq t$$
for every $s$ in $S$ and every $t$ in $T$. Then $S$ has a supremum, and $T$ for every $s$ in $S$ and every $t$ in $T$. Then $S$ has a supremum, and $T$

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@ -11,7 +11,7 @@
\header{Useful Facts About Sets}{Herbert B. Enderton} \header{Useful Facts About Sets}{Herbert B. Enderton}
\section*{\proceeding{Lemma 0A}}% \section*{\proceeding{Lemma 0A}}%
\hyperlabel{sec:lemma-0a}% \label{sec:lemma-0a}
Assume that $\langle x_1, \ldots, x_m \rangle = Assume that $\langle x_1, \ldots, x_m \rangle =
\langle y_1, \ldots, y_m, \ldots, y_{m+k} \rangle$. \langle y_1, \ldots, y_m, \ldots, y_{m+k} \rangle$.

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@ -13,7 +13,7 @@ We assume there exists a class $\mathscr{M}$ of measurable sets in the plane and
properties: properties:
\section*{\defined{Nonnegative Property}}% \section*{\defined{Nonnegative Property}}%
\hyperlabel{sec:nonnegative-property}% \label{sec:nonnegative-property}
For each set $S$ in $\mathscr{M}$, we have $a(S) \geq 0$. For each set $S$ in $\mathscr{M}$, we have $a(S) \geq 0$.
@ -24,7 +24,7 @@ For each set $S$ in $\mathscr{M}$, we have $a(S) \geq 0$.
\end{axiom} \end{axiom}
\section*{\defined{Additive Property}}% \section*{\defined{Additive Property}}%
\hyperlabel{sec:additive-property}% \label{sec:additive-property}
If $S$ and $T$ are in $\mathscr{M}$, then $S \cup T$ and $S \cap T$ are in If $S$ and $T$ are in $\mathscr{M}$, then $S \cup T$ and $S \cap T$ are in
$\mathscr{M}$, and we have $a(S \cup T) = a(S) + a(T) - a(S \cap T)$. $\mathscr{M}$, and we have $a(S \cup T) = a(S) + a(T) - a(S \cap T)$.
@ -36,7 +36,7 @@ If $S$ and $T$ are in $\mathscr{M}$, then $S \cup T$ and $S \cap T$ are in
\end{axiom} \end{axiom}
\section*{\defined{Difference Property}}% \section*{\defined{Difference Property}}%
\hyperlabel{sec:difference-property}% \label{sec:difference-property}
If $S$ and $T$ are in $\mathscr{M}$ with $S \subseteq T$, then $T - S$ is in If $S$ and $T$ are in $\mathscr{M}$ with $S \subseteq T$, then $T - S$ is in
$\mathscr{M}$, and we have $a(T - S) = a(T) - a(S)$. $\mathscr{M}$, and we have $a(T - S) = a(T) - a(S)$.
@ -48,7 +48,7 @@ If $S$ and $T$ are in $\mathscr{M}$ with $S \subseteq T$, then $T - S$ is in
\end{axiom} \end{axiom}
\section*{\defined{Invariance Under Congruence}}% \section*{\defined{Invariance Under Congruence}}%
\hyperlabel{sec:invariance-under-congruence}% \label{sec:invariance-under-congruence}
If a set $S$ is in $\mathscr{M}$ and if $T$ is congruent to $S$, then $T$ is If a set $S$ is in $\mathscr{M}$ and if $T$ is congruent to $S$, then $T$ is
also in $\mathscr{M}$ and we have $a(S) = a(T)$. also in $\mathscr{M}$ and we have $a(S) = a(T)$.
@ -72,7 +72,7 @@ If the edges of $R$ have lengths $h$ and $k$, then $a(R) = hk$.
\end{axiom} \end{axiom}
\section*{\proceeding{Exhaustion Property}}% \section*{\proceeding{Exhaustion Property}}%
\hyperlabel{sec:exhaustion-property}% \label{sec:exhaustion-property}
Let $Q$ be a set that can be enclosed between two step regions $S$ and $T$, so Let $Q$ be a set that can be enclosed between two step regions $S$ and $T$, so
that that

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@ -9,7 +9,7 @@
\begin{document} \begin{document}
\section{\proceeding{Sum of Arithmetic Series}}% \section{\proceeding{Sum of Arithmetic Series}}%
\hyperlabel{sec:sum-arithmetic-series}% \label{sec:sum-arithmetic-series}
Let $(a_i)_{i \geq 0}$ be an arithmetic sequence with common difference $d$. Let $(a_i)_{i \geq 0}$ be an arithmetic sequence with common difference $d$.
Then for some $n \in \mathbb{N}$, Then for some $n \in \mathbb{N}$,

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@ -9,7 +9,7 @@
\begin{document} \begin{document}
\section{\proceeding{Sum of Geometric Series}}% \section{\proceeding{Sum of Geometric Series}}%
\hyperlabel{sec:sum-geometric-series}% \label{sec:sum-geometric-series}
Let $(a_i)_{i \geq 0}$ be a geometric sequence with common ratio $r \neq 1$. Let $(a_i)_{i \geq 0}$ be a geometric sequence with common ratio $r \neq 1$.
Then for some $n \in \mathbb{N}$, Then for some $n \in \mathbb{N}$,

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@ -16,9 +16,6 @@
\hypersetup{colorlinks=true, urlcolor=blue} \hypersetup{colorlinks=true, urlcolor=blue}
\newcommand{\leanref}[2]{\color{blue}$\pmb{\exists}\;{-}\;$\href{#1}{#2}} \newcommand{\leanref}[2]{\color{blue}$\pmb{\exists}\;{-}\;$\href{#1}{#2}}
\newcommand{\hyperlabel}[1]{%
\label{#1}%
\hypertarget{#1}{}}
% ======================================== % ========================================
% Environments % Environments