PQG asks for the "lesser" value from P and Q (the one to the left in the ordered set {1,2,0}). We can also express this as min(P,Q).
PQH asks for the greater value from P and Q (the value to the right). This is max(P,Q)
PQI calls for the sum of the values of P and Q.
PQJ calls for the product of the values of P and Q.
PQK asks for the difference of P and Q (with P as the minuend).
If we go to still higher value systems, we find that only PQG and PQH allow a universal formula: PQGZ is equivalent in any value logic to PZQZH, while PQHZ is equivalent to PZQZG. In a strictly two-value logic, PQG produces the same truth table as PQO while PQH produces the same truth table as PQA, and we find these equivalences are our familiar DeMorgan's Laws.
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