"There's one of these pseudo-proofs for ""1 = 0"", too; it basically goes like this: 0 = 0 + 0 + 0 + ... = (1 - 1) + (1 - 1) + ...""; using associativity, ""(1 - 1) + (1 - 1) + ... = 1 + (-1 + 1) + (-1 + 1) + ... = 1 + 0 + 0 + ... = 1"". What's invalid here is that the law of associativity does not hold for infinite sums that aren't absolutely convergent.   00:12 25 Jun 2003 (UTC)"