Categorical semantics

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== Categories recalled ==
 
== Categories recalled ==
  +
See <ref>{{BibEntry|bibtype=book|author=MacLane, Saunders|title=Categories for the Working Mathematician|publisher=Springer Verlag,year=1971,volume=5,series=Graduate Texts in Mathematics}}</ref>for a more detailed introduction to category theory.
   
 
=== Monoidal categories ===
 
=== Monoidal categories ===
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commute.
 
commute.
 
}}
 
}}
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== References ==
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<references />

Revision as of 18:01, 23 March 2009

TODO: why categories? how to extract categorical models? etc.

Categories recalled

See [1]for a more detailed introduction to category theory.

Monoidal categories

Definition (Monoidal category)

A monoidal category (\mathcal{C},\otimes,I) is a category \mathcal{C} equipped with

  • a functor \otimes:\mathcal{C}\times\mathcal{C}\to\mathcal{C} called tensor product,
  • an object I called unit object,
  • three natural isomorphisms of components

\alpha_{A,B,C}:(A\otimes B)\otimes C\to A\otimes (B\otimes C)
\qquad
\lambda_A:I\otimes A\to A
\qquad
\rho_A:A\otimes I\to A

called respectively associator, left unitor and right unitor,

such that

  • for every objects A,B,C,D in \mathcal{C}, the diagram

commutes,

  • for every objects A and B in \mathcal{C}, the diagrams

commute.

References

  1. MacLane, Saunders. Categories for the Working Mathematician.
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