At this point, it should be stated that the,（·）symbol used in the expression A·B·C is the AND operator and indicates logical multiplication. Forexample, condition 8 in Figure 6-5 can be interpreted as 1·l·I＝1; whereas condition 7 can be interpreted as 1·1·0＝0．
Using the same approach, we find that all other condition（1through6） also produce a zero. It is important to remember that in the binary system, a 2：annot exist一only I's and O's. As with ordinary algebra, the operator symbol(.)can be omitted: thus,A·B•C=ABC and is read "A AND B AND C"。