Commit f09cd666 by Allan Blanchard

### [wp/doc] Improves induction tactic documentation

parent 559ae77d
 ... ... @@ -446,14 +446,17 @@ n|k, n|k', & (k/n).a = (k'/n).b &\Longleftrightarrow& k.a = k'.b \paragraph{Induction} Start a proof by integer induction \\ The user select any integer expression $e$ in the proof and a base value $b$ (which defaults to 0). The tactic generates a proof by strong (integer) induction on $e$, that is, the base case $e = b$ and then the cases $e < b$ and $b < e$. Formally: $\TACTIC{\Delta\models\,G}{% \begin{array}[t]{llll} \Delta, & G[e \leftarrow n], & n = b & \models G[e \leftarrow n] \\ \Delta, & G[e \leftarrow i], & b \leq i < n & \models G[e \leftarrow n] \\ \Delta, & G[e \leftarrow i], & n < i \leq b & \models G[e \leftarrow n] 0). The tactic generates a proof by induction on e, that is, the base case e = b and then the cases e < b and b < e. Formally, the goal \Delta\models\,G is first generalized into \Delta',P(e)\models\,Q(e). Then we proceed by strong (integer) induction over n for G(n) \equiv P(n)\models\,Q(n): \[\TACTIC{\Delta\models\,G(n)}{% \begin{array}[t]{lll} \Delta', & n = b & \models G(n) \\ \Delta', G(k), & b \leq i < n & \models G(n) \\ \Delta', G(k), & n < i \leq b & \models G(n) \end{array}}$ \paragraph{Overflow} Integer Conversions \\ ... ...
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