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Quote: Boole uses and, or, not, and complement; communtative law and idempotent law

topics > all references > references a-b > QuoteRef: boolG_1854 , p. 28 II.6



Topic:
logic

Quotation

Let it further be agreed, that by the combination xy shall be represented that class of things to which the names or descriptions represented by x and y are simultaneously applicable. ... [p. 29] First, it is evident, that ... the order in which two symbols are written is indifferent. ... Hence we have, xy=yx. ... [p.31] if the two symbols have exactly the same signification, their combination expresses no more than either of the symbols take alone would do. In such case we should therefore have xy=x ... [which if we substitute 'x' for 'y', we get xx=x which] assumes the form x^2=x. [Also '-' for not, '1-x' or x-bar for complement, and '+' for or]   Google-1   Google-2

Published before 1923


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Topic: logic (84 items)

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