 Finally in “On the Algebra of Logic: A contribution to the philosophy of notation” (1885a) all of these developments—(i) \(\Sigma\) (sum) for some and \(\Pi\) (product) for all, (ii) utilizing coefficients and their subscripts to drop denotation of individuals (e.g., from \((l)_{ij} (A_{i}: A_{j})\) to \((l)_{ij}\)), (iii) mixing \(\Sigma\) and \(\Pi\), and (iv) omitting the “\(&gt;0\)” part—have become official: