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In mathematics and computer science, the BIT predicate or Ackermann coding, sometimes written BIT(''i'', ''j''), is a predicate which tests whether the ''j''th bit of the number ''i'' is 1, when ''i'' is written in binary. ==History== The BIT predicate was first introduced as the encoding of hereditarily finite sets as natural numbers by Wilhelm Ackermann in his 1937 paper (''The Consistency of General Set Theory''). Each natural number encodes a finite set and each finite set is represented by a natural number. This mapping uses the binary numeral system. If the number ''n'' encodes a finite set ''A'' and the ''i''th binary digit of ''n'' is 1 then the set encoded by ''i'' is an element of ''A''. The Ackermann coding is a primitive recursive function. 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「BIT predicate」の詳細全文を読む スポンサード リンク
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