A polygraph signature, , is given by a set of objects, , and a set of polyedges for every two lists of objects .

There are two notions of polyquiver morphism: rigid polyquiver morphism and expanding polyquiver morphism. These correspond to the category of sets and the Kleisli category of the list monad, respectively.
Notes.
- underlying polyquiver of a monoidal category
- unit of the polyquiver-monoidal adjunction
- polycategory: a polyquiver induces a free polycategory
See also.
References
- The Geometry of Tensor Calculus I (Joyal, Street), Definition 1.4 (called tensor scheme).
Tags: signature, strict monoidal category.
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