Help:Proofs

Proofs make up the main part of. This page lists information regarding their page structure.

One theorem per page
The rule is to present only one theorem per page. Theorems with more than one statement have to be refactored. Reasons not to allow multiple results are:
 * If there are Multiple Proofs of one or all of the statements, organizing the proofs becomes impractical.
 * The page title becomes less meaningful.

In order to maintain an overview of related theorems, a page called Properties of (Something) can be created, with multiple theorems (but not the proofs) transcluded.

For an example of how this is done, see Trigonometric Identities.

Equivalence proofs are an exception to this rule: they may show the equivalence between more than two statements. For the precise policies on it, see Help:Equivalence Proofs.

Multiple Proofs

 * See also: Help:Multiple Proofs

strives to present as many proofs as possible, including multiple proofs of the same theorem. Each proof is placed on a subpage and transcluded as a separate section.

Page structure
Proofs follow the standard structure of pages, as explained at Help:Page Structure. We list here additional elements that are specific to proofs.

Lemmas
Lemmas that do not otherwise merit their own page, are put on a subpage of the proof page. They are: In order to keep pages concise, it is usually a good idea not to transclude the proof of the lemma:
 * transcluded below the "Proof" section heading
 * followed by a horizontal line.

...

Second transcluded lemma
The rest of the proof.

Corollaries
Corollaries are treated like lemmas, but are transcluded right before the "Proof" section heading.

Q.E.D

 * For the mathematical context, see Definition:QED

Each proof, whether of a theorem or a lemma, is concluded using a Halmos Symbol, which can either be $\blacksquare$ or $\square$. It has multiple advantages:


 * It gives a clear indication of the end of the proof.
 * The qed template adds the page to the Proven Results category. This allows to count the number of proofs.

For instructions, see the qed template.

Equivalence Proofs
Proofs that show the equivalence of two or more statements are subject to a particular structure. See Help:Equivalence Proofs.

Proofs by Contradiction
Template:AimForCont

Also see

 * Help:Definitions