Discrete Category on Set is Discrete Category
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![]() | Work In Progress In particular: Theorem can't be formulated atm, what is up now must move to Definition:Set Category (not to be confused with Definition:Category of Sets) You can help $\mathsf{Pr} \infty \mathsf{fWiki}$ by completing it. To discuss this page in more detail, feel free to use the talk page. When this work has been completed, you may remove this instance of {{WIP}} from the code. |
Theorem
Let $S$ be a set.
Let $\map {\mathbf {Dis} } S$ be the discrete category on $S$.
Then $\map {\mathbf {Dis} } S$ determines a unique (up to isomorphism discrete category $\map {\mathbf {Dis} } S$ whose objects precisely comprise $S$.
![]() | This article is complete as far as it goes, but it could do with expansion. In particular: That is, $\mathbf {Dis}: \mathbf {Set} \to \mathbf {Cat}$ is a functor (with left inverse $\mathbf {ob}$) You can help $\mathsf{Pr} \infty \mathsf{fWiki}$ by adding this information. To discuss this page in more detail, feel free to use the talk page. When this work has been completed, you may remove this instance of {{Expand}} from the code.If you would welcome a second opinion as to whether your work is correct, add a call to {{Proofread}} the page. |
Proof
![]() | This needs considerable tedious hard slog to complete it. In particular: Trivial. To discuss this page in more detail, feel free to use the talk page. When this work has been completed, you may remove this instance of {{Finish}} from the code.If you would welcome a second opinion as to whether your work is correct, add a call to {{Proofread}} the page. |
$\blacksquare$
Sources
- 2010: Steve Awodey: Category Theory (2nd ed.) ... (previous) ... (next): $\S 1.4.12$