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diff --git a/content/zettel/3a8g2d.md b/content/zettel/3a8g2d.md new file mode 100644 index 0000000..48b5a44 --- /dev/null +++ b/content/zettel/3a8g2d.md @@ -0,0 +1,44 @@ ++++ +title = "A Possible Destruction Proof" +date = "2022-06-28" +author = "Yann Herklotz" +tags = [] +categories = [] +backlinks = ["3a8g2c"] +forwardlinks = ["3a8g2b1", "3a8g2e"] +zettelid = "3a8g2d" ++++ + +The idea hinges on the following lemma, which talks about a path $p$ +from nodes $n$ to $m$, an arbitrary predicate $\mathcal{P}$ which gets +simplified over that path into $\mathcal{P}'$, and finally an execution +along a path from $n$ with register state $R$ to $m$ with register state +$R'$. The execution of the predicate $P$ with $R'$ should give the same +result as executing the predicate $P'$ with the initial state $R'$. + +```{=latex} +\begin{gather*} +\frac{\begin{array}{c} + S^p(\mathcal{P}) = \mathcal{P}' \\ + n, R \overset{p}{\longrightarrow^*} m, R' +\end{array}}{ + R', \mathcal{P} \Downarrow \lfloor b \rfloor \Longleftrightarrow R, \mathcal{P}' +\Downarrow \lfloor b \rfloor +} +\end{gather*} +``` +However, in addition to that we will also have to prove the +generalisation of the simplification ([\#3a8g2b1]) to show that this has +been done along the path of execution. + +The idea, finally, is that during the proof of semantic preservation, a +path $n\rightsquigarrow_p m$, as well as the execution along that path +$n, R\overset{p}{\longrightarrow^*} m, R'$ are remembered, so that once +a γ function is reached, the lemma above can be applied. It might also +be true that: + +$$ \frac{n, R \overset{p}{\longrightarrow^*} m, R'}{n \rightsquigarrow_p m} $$ + +In which case the lemma can be simplified. + + [\#3a8g2b1]: /zettel/3a8g2b1 |