Difference between revisions of "TU Wien:Einführung in wissensbasierte Systeme VU (Egly)/Übungen WS12/Blatt 1 - Beispiel 4"

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(Die Seite wurde neu angelegt: „ Give a proof or a counter-example for the following statements: (a) If <math>\phi</math> is a '''contradiction''', then <math>\phi</math> is a tautology and <…“)
 
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Give a proof or a counter-example for the following statements:
 
Give a proof or a counter-example for the following statements:
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(a) If <math>\phi</math> is a '''contradiction''', then <math>\phi</math> is a tautology and <math>\psi</math> is a '''contradiction'''.
 
(a) If <math>\phi</math> is a '''contradiction''', then <math>\phi</math> is a tautology and <math>\psi</math> is a '''contradiction'''.
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(b) if <math>\phi \land \psi</math> is a '''tautology''', then <math>\phi</math> is a '''tautology''' or <math>\psi</math> is a '''tautology'''.
 
(b) if <math>\phi \land \psi</math> is a '''tautology''', then <math>\phi</math> is a '''tautology''' or <math>\psi</math> is a '''tautology'''.
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(c)
 
(c)
  

Revision as of 20:38, 27 October 2012

Give a proof or a counter-example for the following statements:

(a) If \phi is a contradiction, then \phi is a tautology and \psi is a contradiction.

(b) if \phi \land \psi is a tautology, then \phi is a tautology or \psi is a tautology.

(c)


Lösungsvorschlag