Definition:Insertion of Generators
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Definition
Let $S$ be a set, and let $S^*$ be its Kleene closure.
The insertion of generators (into $S^*$) is the mapping $i: S \to S^*$ defined by:
- $i \left({s}\right) := \left\langle{s}\right\rangle$
that is, it sends any element $s$ of $S$ to the one-term sequence containing only $s$.
Also defined as
The mapping $i$ in the definition of a free monoid is also called insertion of generators.
From Kleene Closure is Free Monoid, we see that this viewpoint generalizes the definition given above.
Sources
- 2010: Steve Awodey: Category Theory (2nd ed.) ... (previous) ... (next): $\S 1.7$