Modus Ponendo Tollens/Proof Rule/Tableau Form

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Tableau Form of Modus Ponendo Tollens

Let $\phi \land \psi$ be a well-formed formula in a tableau proof whose main connective is the conjunction operator.

The Modus Ponendo Tollens is invoked for $\neg \left({\phi \land \psi}\right)$ in either of the two forms:


Form 1
Pool:    The pooled assumptions of $\neg \left({\phi \land \psi}\right)$      
The pooled assumptions of $\phi$      
Formula:    $\neg \psi$      
Description:    Modus Ponendo Tollens      
Depends on:    The line containing the instance of $\neg \left({\phi \land \psi}\right)$      
The line containing the instance of $\phi$      
Abbreviation:    $\text{MPT}_1$      


Form 2
Pool:    The pooled assumptions of $\neg \left({\phi \land \psi}\right)$      
The pooled assumptions of $\psi$      
Formula:    $\neg \phi$      
Description:    Modus Ponendo Tollens      
Depends on:    The line containing the instance of $\neg \left({\phi \land \psi}\right)$      
The line containing the instance of $\psi$      
Abbreviation:    $\text{MPT}_2$