K-comonoid

Grouplike in a K-monoid

In a K-comonoid A, the comultiplication can almost never be the diagonal map, since this is not linear. It can however act diagonally on a subset of elements. A grouplike of A is a nonzero element 𝑥 ∈A such that Δ𝑥 =𝑥 ⊗𝑥. #m/def/hopf

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The set of all grouplikes in A is denoted Gr⁡A.

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