Minimizing and mapping sequential circuits

SHANNON'S original paper suggesting a modification of the classical Boolean algebra of symbolic logic to a form of switching algebra led to the development among switching and computer designers of many special techniques.
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Recent interest in the field is rapidly developing methods well within the reach of the occasional switching engineer who finds a moderately complex relay circuit necessary to the operation or sequencing of another design. Reference is made to these papers for a brief summary of the binary nomenclature and operators of switching algebra.4,5 The approach suggested here assures the designer that he is manipulating an adequate number of relays, and provides a pictorial work sheet that keeps track of all contact positions. The work sheet permits easy recognition of possible holding circuit difficulties. Negation is proposed as the switching-algebra operator to denote shunt contacts, and is consistent with the mapping procedure.