Decisive differences and partial differences for stuck-at fault detection in MVL circuits

An extension of the exclusive-OR operator is defined for multivalued algebra. This operator, called the decisive difference and denoted (-), is particularly useful for multivalued stuck-at fault detection experiments. The (-) operator is used in the definition of functional transformations called partial differences. Basic properties of partial differences are presented, and it is shown how they can be used to find stuck-at fault sets of tests for sum-of-products form functions in the chain lattice algebra. The method uses strictly algebraic manipulation rather than exhaustive map searching. Partial differences can also be used to find sets of tests for internal and multiple stuck-at faults. Multivalued derivatives described by several other authors and Boolean differences are special cases of partial differences.<>