law of double negation

短语

释义与例句

n.
  1. 1.

    The statement that the negation of the negation of A implies A, for any proposition A. Stated symbolically: ¬¬A→A.

    数学 哲学

    The law of double negation is not valid intuitionistically. To show this with Heyting algebra semantics, let A#61;(0,1)#92;cup(1,2). Then #92;negA#61;(-#92;infty,0)#92;cup(2,#92;infty), #92;neg#92;negA#61;(0,2), #92;neg#92;negA#92;toA#61;(-#92;infty,1)#92;cup(1,#92;infty)#92;ne#92;mathbb#123;R#125;.