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Re: [xsl] () eq () vs () = ()
Subject: Re: [xsl] () eq () vs () = () From: Andrew Welch <andrew.j.welch@xxxxxxxxx> Date: Mon, 3 Oct 2011 15:20:06 +0100 |
On 3 October 2011 15:15, Wolfgang Laun <wolfgang.laun@xxxxxxxxx> wrote: > Just think of the universal quantifier "forall" (every $x in X > satisfies P) as a conjunction over zero or more elements. Its > initialization must be true (as the initial value for a product must > be 1). Therefore, the "forall" for an empty set is true. > > The quantifier "exists" (some $x in X satisfies P) is a disjunction > over elements, and its initialization must be false (as the initial > value for a sum must be 0). Hence, the "exists" for an empty set X is > false. Thanks - the 'initialization' is how I saw it - deep-equal() / every starts from a position of true and looks for a reason to be false, and =/some starts from a position of false and looks for a reason to be true. Not such faulty logic after all. -- Andrew Welch http://andrewjwelch.com
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