Proof of p^(qvr) <=> (p^q)v(p^r)

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Discussion Overview

The discussion revolves around proving the equivalence of the logical expression p^(qvr) and (p^q)v(p^r) within the framework of propositional calculus. Participants explore both semantic and syntactic methods for the proof, including the use of truth tables and other logical reasoning techniques.

Discussion Character

  • Exploratory, Debate/contested, Homework-related

Main Points Raised

  • One participant suggests using truth tables as a quick method for a semantic proof.
  • Another participant expresses uncertainty about the use of truth tables and mentions a potential semantic proof they have in mind, though they lack confidence in it.
  • A participant questions the distinction between semantic and syntactic proofs and encourages sharing ideas for further discussion.
  • There is a suggestion that a contradiction might be used for the syntactical proof, but it is noted that this approach could be complex.

Areas of Agreement / Disagreement

Participants have not reached a consensus on the best method for proving the equivalence, and multiple approaches are being considered, indicating ongoing debate and exploration of ideas.

Contextual Notes

Participants have not fully defined their terms, such as "semantical proof" and "syntactical proof," which may lead to varying interpretations of the methods discussed.

evagelos
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How do we prove in propositional calculus :

...p^(qvr) <===> (p^q)v(p^r) semantically and syntactically
 
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Well, what have you already come up with?
 
Comparing truth tables will do it quickly and neatly. Are you not allowed to use that method?
 
I had to Google as well, as far as I http://www.rci.rutgers.edu/~cfs/472_html/Logic_KR/proplogic_proofs472.html , using truth tables would be the semantic proof.
 
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Semantical proof without using true tables ,i have one in mind but i am not very positive about it.Then syntactically how about a contradiction you think it could work ,although it looks a bit messy
 
It is not quite clear to me what you mean by a semantical proof, and a syntactical one.
Also, if you would post your idea we can have a look at it. Maybe you are on the right track but just need a last push, or maybe you even got it right but lack the confidence :wink:
 

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