In many ways, truth tables are directly connected to digital logic circuits; in the case of computers, the terms would be AND, OR, NAND, NOR, NOT, XOR, or the “gates” that open and close in response to such terms. In such a circuit, values at each point can take on values of only true (1) or false (0); this is also known as the computer binary system. In general, there is also a three-valued logic, in which possible values are true, false, and “undecided.” A further generalization called fuzzy logic examines the “truth” as a continuous quantity ranging from 0 to 1. (For more about fuzzy logic and computers, see “Math in Computing.”)