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ya - [Y]oneda contr[a]variant

Precedence: 8

`ya` - [Y]oneda contr[A]variant

Looks like a circle with a white bullet point inside. This white bullet point represents contravariant position of a parameter we are going to map.

`ya` : t a `AR_` into (from o a) (t o)

You are not going to use it often though.