| context | $\langle\!\langle M,*\rangle\!\rangle$ … monoid |
| definiendum | $\langle\!\langle S,*\rangle\!\rangle\in$ it |
| inclusion | $S\in$ closed monoid subset of $\langle\!\langle M,*\rangle\!\rangle$ |
| exists | $e\in S$ |
| postulate | $e$ … unit of $\langle\!\langle M,*\rangle\!\rangle$ |