The logical sum applied to two propositions returns their disjunction.

For the logical sum, there is a procedure that assigns a specific weight to each term in the logical relation.

-"A ruthlessly logical summing up of the six Spro-cas commissions.

The four fundamental functions are the contradictory function, the logical sum, the logical product, and the implicative function.

Any propositional formula can be reduced to the "logical sum" (OR) of the active (i.e. "1"- or "T"-valued) minterms.

The fundamental functions of propositions: "the Contradictory Function" symbolized by " " and the "Logical Sum or Disjunctive Function" symbolized by " " being taken as primitive and logical implication defined (the following example also used to illustrate 9.