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voved vo teorijata na mno@estvata i matemati^kata logika

voved vo teorijata na mno@estvata i matemati^kata logika

voved vo teorijata na mno@estvata i matemati^kata logika

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Primer:<br />

1. p∧(p∨q) i p se logi~ki ekvivalentni formuli so funkcii <strong>na</strong> vistinitost<br />

f i g soodvetno. Toga{ f(T,T)=f(T,⊥)=T=g(T); f(⊥, T)=f(⊥,⊥)=⊥=g(⊥).<br />

Z<strong>na</strong>~i, i dvete funkcii <strong>vo</strong> su{ti<strong>na</strong> zavisat samo od ed<strong>na</strong> promenliva, a<br />

vtorata promenliva <strong>na</strong> funkcijata f e fiktiv<strong>na</strong>, pa iako tie dve funkcii<br />

nemaat isti domeni, mo`eme da gi smetame za ed<strong>na</strong>kvi.<br />

Se postavuva pra{awe dali site funkcii <strong>na</strong> vistinitost se<br />

generirani so iskazni formuli.<br />

5.1 o Sekoja funkcija <strong>na</strong> vistinitost e opredele<strong>na</strong> od iskaz<strong>na</strong><br />

formula koja{to gi sodr`i svrznicite ¬, ∨ i ∧.<br />

Dokaz: Neka f(x 1 ,...,x n ) e dade<strong>na</strong> funkcija <strong>na</strong> vistinitost. f mo`e da se<br />

pretstavi so tablica {to sodr`i 2 n redici, pri {to sekoj red sodr`i nekoe<br />

pridru`uvawe <strong>na</strong> vrednosti <strong>na</strong> vistinitost <strong>na</strong> promenlivite, sledeno so<br />

vrednosta <strong>na</strong> vistinitost <strong>na</strong> funkcijata f(x 1 ,...,x n ). Ako 1

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