User:Prime.mover/Proof Structures

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Ordinary proofs

{{begin-eqn}}
{{eqn | q = 
      | l = 
      | o = =
      | r = 
      | c = 
}}
{{eqn | ll= \leadsto
      | l = 
      | o = =
      | r = 
      | c = 
}}
{{end-eqn}}

and so on.

Axiom schemata

{{begin-axiom}}
{{axiom | n = \text A 0
        | lc= 
        | q = 
        | t = 
        | rc= 
}}
{{axiom | n = \text A 1
        | lc= 
        | q = 
        | m = 
        | rc= 
}}
{{axiom | n = \text A 2
        | lc= 
        | q = 
        | ml= 
        | mo= 
        | mr= 
        | mm= 
        | rc= 
}}
{{axiom | n = \text A 3
        | lc= 
        | q = 
        | tl= 
        | to= 
        | tr= 
        | rc= 
}}
{{end-axiom}}

and so on.

See {{Axiom}}

Definition

== Definition ==
<onlyinclude>
Definition
</onlyinclude>

=== [[Definition:Definiend/Symbol|Symbol]] ===
{{:Definition:Definiend/Symbol}}

== [[Definiend/Examples|Examples]] ==
{{:Definiend/Examples}}

== [[Definition:Definiend/Also known as|Also known as]] ==
{{:Definition:Definiend/Also known as}}

== Also see ==

{{Link-to-category|Definiend|definiend}}

{{NamedforDef|eponym|cat = surname}}

== [[Definition:Definiend/Historical Note|Historical Note]] ==
{{:Definition:Definiend/Historical Note}}

== [[Definition:Definiend/Linguistic Note|Linguistic Note]] ==
{{:Definition:Definiend/Linguistic Note}}

== Sources ==

{{NoSources}}

[[Category:Definitions/Definiend]]
== Examples of [[Definition:Definiend|Definiends]] ==
<onlyinclude>
=== [[Definiend/Examples/Arbitrary Example 1|Arbitrary Example]] ===
{{:Definiend/Examples/Arbitrary Example 1}}</onlyinclude>

[[Category:Examples of Definiends]]
{{ExampleCategory|def = Definiend}}

[[Category:Definiends]]
#Redirect [[Definition:Definiend]]

[[Category:Definitions/Definiends]]
== [[Definition:Definiend|Definiend]]: Also known as == 
<onlyinclude>
A '''[[Definition:Definiend|definiend]]''' is also known as a '''[[Definition:Alternative Definiend|alternative definiend]]'''.
</onlyinclude>

== Sources ==

{{SourceReview}}

[[Category:Definitions/Definiends]]
== Historical Note on [[Definition:Definiend|Definiend]] ==
<onlyinclude>

</onlyinclude>

== Sources ==

{{NoSources}}

[[Category:Historical Notes]]
== Linguistic Note on [[Definition:Definiend|Definiend]] ==
<onlyinclude>

</onlyinclude>

== Sources ==

{{SourceReview}}

[[Category:Linguistic Notes]]
== [[Definition:Definiend|Definiend]]: [[Symbols:x/Definiend|Symbol]] ==
<onlyinclude>
The [[Symbols:x/Definiend|symbol]] for the '''[[Definition:Definiend|definiend]]''' is $...$.
</onlyinclude>

== Sources ==

{{SourceReview}}

[[Category:Definitions/Definiends]]

Theorems

== Theorem ==
<onlyinclude>
Let $...$ be a [[Definition:definiend|definiend]].
</onlyinclude>

== Proof ==

{{ProofWanted}}

== Also see ==

{{Namedfor|eponym|cat = surname}}

== [[Theorem/Historical Note|Historical Note]] ==
{{:Theorem/Historical Note}}

== Sources ==

{{SourceReview}}

[[Category:definiends]]

Disambiguation

{{Disambiguation}}

=== [[Definition:definiend (context)|definiend (context)]] ===
{{:Definition:definiend (context)}}

=== [[Definition:definiend (context)|definiend (context)]] ===
{{:Definition:definiend (context)}}

[[Category:Definitions/definiends]]


Definition Equivalences

== Theorem ==

{{TFAE|def = [definiend] }}

=== [[Definition:[definiend]/Definition 1|Definition $1$]] ===
{{:Definition:[definiend]/Definition 1}}
=== [[Definition:[definiend]/Definition 2|Definition $2$]] ===
{{:Definition:[definiend]/Definition 2}}

== Proof ==

=== Definition $(1)$ implies Definition $(2)$ ===

Let $...$ be a [[Definition:[definiend]/Definition 1|[definiend] by definition $1$]].

Then by definition:
: [Definition 1 of definiend]

:
:

Thus $...$ is a [[Definition:[definiend]/Definition 2|[definiend] by definition $2$]].
{{qed|lemma}}


=== Definition $(2)$ implies Definition $(1)$ ===

Let $...$ be a [[Definition:[definiend]/Definition 2|[definiend] by definition $2$]].

Then by definition:
: [Definition 2 of definiend]

:
:
:

Thus $...$ is a [[Definition:[definiend]/Definition 1|[definiend] by definition $1$]].
{{qed|lemma}}

[[Category:[definiend]]]

Technical Notes

== Technical Note for [[Definition:definiend|definiend]] ==
<onlyinclude>
{{LatexFor|for = <latex-code> }}

When either of the arguments is a single character, it is usual to omit the [[Symbols:Braces|braces]]:
:<code><latex-code></code>
</onlyinclude>

This command is specific to {{ProofWiki}}.

[[Category:Technical Notes]]
[[Category:Definitions/definiends]]

Search Convenience

#Redirect [[target]]

[[Category:Search Convenience]]

Integration by Parts

With a view to expressing the [[Definition:Primitive (Calculus)|primitive]] in the form:
:$\ds \int u \frac {\d v} {\d x} \rd x = u v - \int v \frac {\d u} {\d x} \rd x$

let:
{{begin-eqn}}
{{eqn | l = u
      | r = ...
      | c = 
}}
{{eqn | ll= \leadsto
      | l = \frac {\d u} {\d x}
      | r = ...
      | c = link to rule
}}
{{end-eqn}}


and let:
{{begin-eqn}}
{{eqn | l = \frac {\d v} {\d x}
      | r = ...
      | c = 
}}
{{eqn | ll= \leadsto
      | l = v
      | r = ...
      | c = link to rule
}}
{{end-eqn}}


Then:
{{begin-eqn}}
{{eqn | l = \int ...
      | r = \int u \rd v
      | c = 
}}
{{eqn | r = \paren {u} \paren {v} - \int \paren {v} \paren {\frac {\d u} {\d x} } \rd x
      | c = [[Integration by Parts]]
}}
{{eqn | r = ...
      | c = etc
}}
{{end-eqn}}
{{qed}}


Iff Proofs

=== Necessary Condition ===


=== Sufficient Condition ===

Partition Proofs

Testing each of the criteria for a [[Definition:Set Partition|partition]] as follows:

=== Each element in no more than one component ===


Thus each [[Definition:Element|element]] of ... is in no more than one [[Definition:Component of Partition|component]] of ... .
{{qed|lemma}}


=== Each element in at least one component ===


Thus each [[Definition:Element|element]] of ... is in at least one [[Definition:Component of Partition|component]] of ... .
{{qed|lemma}}


=== No component is empty ===


Thus no [[Definition:Component of Partition|component]] of ... is [[Definition:Empty Set|empty]].
{{qed|lemma}}


Thus ... is a [[Definition:Set Partition|partition]] by definition.
{{qed|lemma}}

Metric Space proofs

It is to be demonstrated that $d$ satisfies all the [[Axiom:Metric Space Axioms|metric space axioms]].


=== Proof of {{Metric-space-axiom|1|nolink}} ===

{{begin-eqn}}
{{eqn | l = \map d {x, x}
      | r = 
      | c = Definition of $d$
}}
{{eqn | r = 0
      | c = as ... fulfils {{Metric-space-axiom|1}}
}}
{{end-eqn}}

So {{Metric-space-axiom|1}} holds for $d$.
{{qed|lemma}}


=== Proof of {{Metric-space-axiom|2|nolink}} ===

{{begin-eqn}}
{{eqn | l = \map d {x, y} + \map d {y, z}
      | r = 
      | c = Definition of $d$
}}
{{eqn | r = 
      | c = 
}}
{{eqn | o = \ge
      | r = 
      | c = as ... fulfils {{Metric-space-axiom|2}}
}}
{{eqn | r = \map d {x, z}
      | c = Definition of $d$
}}
{{end-eqn}}

So {{Metric-space-axiom|2}} holds for $d$.
{{qed|lemma}}


=== Proof of {{Metric-space-axiom|3|nolink}} ===

{{begin-eqn}}
{{eqn | l = \map d {x, y}
      | r = 
      | c = Definition of $d$
}}
{{eqn | r = k \cdot \map d {y, x}
      | c = as ... fulfils {{Metric-space-axiom|3}}
}}
{{eqn | r = \map d {y, x}
      | c = Definition of $d$
}}
{{end-eqn}}

So {{Metric-space-axiom|3}} holds for $d$.
{{qed|lemma}}


=== Proof of {{Metric-space-axiom|4|nolink}} ===

{{begin-eqn}}
{{eqn | l = x
      | o = \ne
      | r = y
      | c = 
}}
{{eqn | ll= \leadsto
      | l = ... \map d {x, y}
      | o = >
      | r = 0
      | c = as ... fulfils {{Metric-space-axiom|4}}
}}
{{eqn | ll= \leadsto
      | l = 
      | o = >
      | r = 0
      | c = 
}}
{{eqn | ll= \leadsto
      | l = \map d {x, y}
      | o = >
      | r = 0
      | c = Definition of $d$
}}
{{end-eqn}}

So {{Metric-space-axiom|4}} holds for $d$.
{{qed|lemma}}


Thus $d$ satisfies all the [[Axiom:Metric Space Axioms|metric space axioms]] and so is a [[Definition:Metric|metric]].
{{qed}}

Topology Proofs

Each of the [[Axiom:Open Set Axioms|open set axioms]] is examined in turn:


=== {{Open-set-axiom|1|nolink}} ===

Let $\family {U_i}_{i \mathop \in I}$ be an [[Definition:Indexed Family|indexed family]] of [[Definition:Open Set (Topology)|open sets]] of $T$.

Let $\ds V = \bigcup_{i \mathop \in I} U_i$ be the [[Definition:Union of Family|union]] of $\family {U_i}_{i \mathop \in I}$.

:
:

Hence $V$ is [[Definition:Open Set (Topology)|open]] by definition.
{{qed|lemma}}


=== {{Open-set-axiom|2|nolink}} ===

Let $U$ and $V$ be [[Definition:Open Set (Topology)|open sets]] of $T$.

:
:

Hence $U \cap V$ is [[Definition:Open Set (Topology)|open]] by definition.
{{qed|lemma}}


=== {{Open-set-axiom|3|nolink}} ===

:
:

{{qed|lemma}}


All the [[Axiom:Open Set Axioms|open set axioms]] are fulfilled, and the result follows.
{{qed}}

Equivalence Proofs

Checking in turn each of the criteria for [[Definition:Equivalence Relation|equivalence]]:


=== Reflexivity ===

Thus ... is seen to be [[Definition:Reflexive Relation|reflexive]].
{{qed|lemma}}


=== Symmetry ===

Thus ... is seen to be [[Definition:Symmetric Relation|symmetric]].
{{qed|lemma}}


=== Transitivity ===

Thus ... is seen to be [[Definition:Transitive Relation|transitive]].
{{qed|lemma}}


... has been shown to be [[Definition:Reflexive Relation|reflexive]], [[Definition:Symmetric Relation|symmetric]] and [[Definition:Transitive Relation|transitive]].

Hence by definition it is an [[Definition:Equivalence Relation|equivalence relation]].
{{qed}}

Ordering Proofs

Checking in turn each of the criteria for an [[Definition:Ordering|ordering]]:

=== Reflexivity ===


So ... has been shown to be [[Definition:Reflexive Relation|reflexive]].
{{qed|lemma}}


=== Transitivity ===


So ... has been shown to be [[Definition:Transitive Relation|transitive]].
{{qed|lemma}}


=== Antisymmetry ===


So ... has been shown to be [[Definition:Antisymmetric Relation|antisymmetric]].
{{qed|lemma}}


... has been shown to be [[Definition:Reflexive Relation|reflexive]], [[Definition:Transitive Relation|transitive]] and [[Definition:Antisymmetric Relation|antisymmetric]].

Hence by definition it is an [[Definition:Ordering|ordering]].
{{qed}}

Strict Ordering Proofs

Checking in turn each of the criteria for a [[Definition:Strict Ordering|strict ordering]]:

=== Antireflexivity ===


So ... has been shown to be [[Definition:Antireflexive Relation|antireflexive]].
{{qed|lemma}}


=== Transitivity ===


So ... has been shown to be [[Definition:Transitive Relation|transitive]].
{{qed|lemma}}


=== Asymmetry ===


So ... has been shown to be [[Definition:Asymmetric Relation|asymmetric]].
{{qed|lemma}}


... has been shown to be [[Definition:Antireflexive Relation|antireflexive]], [[Definition:Transitive Relation|transitive]] and [[Definition:Asymmetric Relation|asymmetric]].

Hence by definition it is a [[Definition:Strict Ordering|strict ordering]].
{{qed}}

Semigroup Proofs


Taking the [[Axiom:Semigroup Axioms|semigroup axioms]] in turn:


=== {{SemigroupAxiom|0|nolink}} ===

Thus $...$ and so $...$ is [[Definition:Closed Algebraic Structure|closed]].
{{qed|lemma}}


=== {{SemigroupAxiom|1|nolink}} ===

Thus $...$ is [[Definition:Associative Operation|associative]].
{{qed|lemma}}


The [[Axiom:Semigroup Axioms|semigroup axioms]] are thus seen to be fulfilled, and so $...$ is a [[Definition:Semigroup|semigroup]].
{{qed}}

Group Proofs

Taking the [[Axiom:Group Axioms|group axioms]] in turn:


=== {{GroupAxiom|0|nolink}} ===

Thus $...$ and so $...$ is [[Definition:Closed Algebraic Structure|closed]].
{{qed|lemma}}


=== {{GroupAxiom|1|nolink}} ===

Thus $...$ is [[Definition:Associative Operation|associative]].
{{qed|lemma}}


=== {{GroupAxiom|2|nolink}} ===

Thus $...$ is the [[Definition:Identity Element|identity element]] of $...$.

{{qed|lemma}}


=== {{GroupAxiom|3|nolink}} ===

We have that $...$ is the [[Definition:Identity Element|identity element]] of $...$.


Thus every [[Definition:Element|element]] $...$ of $...$ has an [[Definition:Inverse Element|inverse]] $...$.
{{qed|lemma}}


All the [[Axiom:Group Axioms|group axioms]] are thus seen to be fulfilled, and so $...$ is a [[Definition:Group|group]].
{{qed}}

Semilattice Proofs

Taking the [[Axiom:Semilattice Axioms|semilattice axioms]] in turn:


=== {{Semilattice-axiom|0|nolink}} ===


Thus $...$ is [[Definition:Closed Algebraic Structure|closed]].
{{qed|lemma}}


=== {{Semilattice-axiom|1|nolink}} ===


Thus $...$ is [[Definition:Associative Operation|associative]].
{{qed|lemma}}


=== {{Semilattice-axiom|2|nolink}} ===


Thus $...$ is [[Definition:Commutative Operation|commutative]].
{{qed|lemma}}


=== {{Semilattice-axiom|3|nolink}} ===


Thus $...$ is [[Definition:Idempotent Operation|idempotent]].
{{qed|lemma}}


All the [[Axiom:Semilattice Axioms|semilattice axioms]] are thus seen to be fulfilled, and so $...$ is a [[Definition:Semilattice|semilattice]].
{{qed}}

Group Action Proofs

The [[Axiom:Group Action Axioms|group action axioms]] are investigated in turn.

Let $g, h \in G$ and $s \in S$.


Thus:

{{begin-eqn}}
{{eqn | l = g * \paren {h * s}
      | r = ...
      | c = by definition of $*$
}}
:
:
{{eqn | r = \paren {g \circ h} * s
      | c = by definition of $*$
}}
{{end-eqn}}

demonstrating that {{GroupActionAxiom|1}} holds.


Then:

{{begin-eqn}}
{{eqn | l = e * s
      | r = ...
      | c = 
}}
{{eqn | r = s
      | c = ...
}}
{{end-eqn}}

demonstrating that {{GroupActionAxiom|2}} holds.


The [[Axiom:Group Action Axioms|group action axioms]] are thus seen to be fulfilled, and so $*$ is a [[Definition:Group Action|group action]].
{{qed}}

Ring Proofs

Taking the [[Axiom:Ring Axioms|ring axioms]] in turn:

=== {{Ring-axiom|A|nolink}} ===


=== {{Ring-axiom|M0|nolink}} ===

=== {{Ring-axiom|M1|nolink}} ===


=== {{Ring-axiom|D|nolink}} ===

Proof by Mathematical Induction

The proof proceeds by induction.

For all $n \in \Z_{\ge 0}$, let $\map P n$ be the proposition:

$proposition_n$


$\map P 0$ is the case:

$proposition_0$

Thus $\map P 0$ is seen to hold.


Basis for the Induction

$\map P 1$ is the case:

$proposition_1$


Thus $\map P 1$ is seen to hold.


This is the basis for the induction.


Induction Hypothesis

Now it needs to be shown that if $\map P k$ is true, where $k \ge 1$, then it logically follows that $\map P {k + 1}$ is true.


So this is the induction hypothesis:

$proposition_k$


from which it is to be shown that:

$proposition_{k + 1}$


Induction Step

This is the induction step:

\(\ds \) \(=\) \(\ds \)
\(\ds \leadsto \ \ \) \(\ds \) \(=\) \(\ds \)

So $\map P k \implies \map P {k + 1}$ and the result follows by the Principle of Mathematical Induction.


Therefore:

$\forall n \in \Z_{\ge 0}: proposition_n$


Proof by Complete Induction

The proof proceeds by strong induction.

For all $n \in \Z_{\ge 0}$, let $\map P n$ be the proposition:

$proposition_n$


$\map P 0$ is the case:

$proposition_0$

Thus $\map P 0$ is seen to hold.


Basis for the Induction

$\map P 1$ is the case:

$proposition_1$


Thus $\map P 1$ is seen to hold.


This is the basis for the induction.


Induction Hypothesis

Now it needs to be shown that if $\map P j$ is true, for all $j$ such that $0 \le j \le k$, then it logically follows that $\map P {k + 1}$ is true.


This is the induction hypothesis:

$proposition_k$


from which it is to be shown that:

$proposition_{k + 1}$


Induction Step

This is the induction step:

\(\ds \) \(=\) \(\ds \)
\(\ds \leadsto \ \ \) \(\ds \) \(=\) \(\ds \)

So $\map P k \implies \map P {k + 1}$ and the result follows by the Second Principle of Mathematical Induction.


Therefore:

$proposition_n$


Proof by Finite Induction

The proof will proceed by the Principle of Finite Induction on $\Z_{>0}$.

Let $S$ be the set defined as:

$S := \set {n \in \Z_{>0}: ...}$

That is, $S$ is to be the set of all $n$ such that:

$...$


Basis for the Induction

We have that:

(proof that $1 \in S$)

So $1 \in S$.

This is the basis for the induction.


Induction Hypothesis

It is to be shown that if $k \in S$ where $k \ge 1$, then it follows that $k + 1 \in S$.

This is the induction hypothesis:

$\text {expression for $k$}$


It is to be demonstrated that it follows that:

$\text {expression for $k + 1$}$


Induction Step

This is the induction step:


\(\ds \) \(=\) \(\ds \)
\(\ds \leadsto \ \ \) \(\ds \) \(=\) \(\ds \)

So $k \in S \implies k + 1 \in S$ and the result follows by the Principle of Finite Induction:

$\forall n \in \Z_{>0}: ...$


Proof by Complete Finite Induction

The proof will proceed by the Principle of Complete Finite Induction on $\Z_{>0}$.

Let $S$ be the set defined as:

$S := \set {n \in \Z_{>0}: ...}$

That is, $S$ is to be the set of all $n$ such that:

$...$


Basis for the Induction

We have that:

(proof that $1 \in S$)

So $1 \in S$.

This is the basis for the induction.


Induction Hypothesis

It is to be shown that if $j \in S$ for all $j$ such that $0 \le j \le k$, then it follows that $k + 1 \in S$.


This is the induction hypothesis:

$\forall j \in \Z_{>0}: 1 \le j \le k: \text {expression for $j$}$


It is to be demonstrated that it follows that:

$\text {expression for $k + 1$}$


Induction Step

This is the induction step:


\(\ds \) \(=\) \(\ds \)
\(\ds \leadsto \ \ \) \(\ds \) \(=\) \(\ds \)

So $\forall j \in S: 0 \le j \le k: j \in S \implies k + 1 \in S$ and the result follows by the Principle of Complete Finite Induction:

$\forall n \in \Z_{>0}: ...$


Proof by General Induction

The proof proceeds by general induction.

For all $x \in M$, let $\map P x$ be the proposition:

$\text {proposition}_x$


Basis for the Induction

$\map P \O$ is the case:

$\text {proposition}_\O$

Thus $\map P \O$ is seen to hold.


This is the basis for the induction.


Induction Hypothesis

Now it needs to be shown that if $\map P x$ is true, where $x \in M$, then it logically follows that $\map P {\map g x}$ is true.


So this is the induction hypothesis:

$\text {proposition}_x$


from which it is to be shown that:

$\text {proposition}_{\map g x}$


Induction Step

This is the induction step:

\(\ds \) \(=\) \(\ds \)
\(\ds \leadsto \ \ \) \(\ds \) \(=\) \(\ds \)

So $\map P x \implies \map P {\map g x}$ and the result follows by the Principle of General Induction.


Therefore:

$\forall x \in M: \text {proposition}_x$


Proof by Superinduction

The proof proceeds by superinduction.

For all $x \in M$, let $\map P x$ be the proposition:

$\text {proposition}_x$


Basis for the Induction

$\map P \O$ is the case:

$\text {proposition}_\O$

Thus $\map P \O$ is seen to hold.


This is the basis for the induction.

$\Box$


Induction Hypothesis

Now it needs to be shown that if $\map P x$ is true, where $x \in M$, then it logically follows that $\map P {\map g x}$ is true.


So this is the induction hypothesis:

$\text {proposition}_x$


from which it is to be shown that:

$\text {proposition}_{\map g x}$


Induction Step

This is the induction step:

\(\ds \) \(=\) \(\ds \)
\(\ds \leadsto \ \ \) \(\ds \) \(=\) \(\ds \)

So $\map P x \implies \map P {\map g x}$.

$\Box$


Closure under Chain Unions

It remains to demonstrate closure under chain unions.


Let $\map P x$ be true for all $x \in C$, where $C$ is an arbitrary chain of elements of $M$.

That is:

$\forall x \in C: \text {proposition}_x$



and so:

$\text {proposition}_{\ds \bigcup C}$


That is:

$\forall C: \forall x \in C: \map P x \implies \map P {\ds \bigcup C}$


The result follows by the Principle of Superinduction.

$\Box$


Therefore:

$\forall x \in M: \text {proposition}_x$


Tableau proofs

{| border="1"
|-
! Line !!
! Pool
! Formula
! Rule
! Depends upon
! Notes
|-
| align="right" | <line number> ||
| align="right" | <line numbers>
| $\ldots{}$
| [[link to ProofWiki entry]]
| <line numbers>
|-
| align="right" | <line number> ||
| align="right" | <line numbers>
| $\ldots{}$
| [[link to ProofWiki entry]]
| <line numbers>
|}
...etc.

Puzzle (Dudeney Modern Puzzles)

== {{BookLink|Modern Puzzles|Henry Ernest Dudeney}} by {{AuthorRef|Henry Ernest Dudeney}}: $...$ ==
<onlyinclude>
;<title>

:''<rubric>''
</onlyinclude>

== Solution ==


== Proof ==


== Sources ==

* {{BookReference|Modern Puzzles|1926|Henry Ernest Dudeney|prev = Dudeney's Modern Puzzles/Arithmetical and Algebraical Problems/Money Puzzles/5 - Doubling the Value|next = Dudeney's Modern Puzzles/Arithmetical and Algebraical Problems/Money Puzzles/7 - Generous Gifts}}: Arithmetical and Algebraical Problems: Money Puzzles: $6$. -- Generous Gifts

[[Category:Dudeney's Modern Puzzles]]