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sav08:logic_and_automata_introduction [2008/05/14 10:12] vkuncak |
sav08:logic_and_automata_introduction [2008/05/14 11:06] vkuncak |
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- | ====== Logic and Automata Introduction ====== | + | ====== Logic and Automata - Introduction ====== |
Satisfiability of $F$: is there an interpretation in which $F$ is true. | Satisfiability of $F$: is there an interpretation in which $F$ is true. | ||
Line 14: | Line 14: | ||
More generally, for each formula with free variables, we compute the relation that the formula defines. | More generally, for each formula with free variables, we compute the relation that the formula defines. | ||
- | Example: compute the unary relation (set) corresponding to this formula $F(z)$: | + | === Example === |
+ | |||
+ | Compute the unary relation (set) corresponding to this formula $F(z)$: | ||
\[ | \[ | ||
\exists x. \exists y.\ z = 2 x + 1 \land z = 3 y + 2 | \exists x. \exists y.\ z = 2 x + 1 \land z = 3 y + 2 | ||
\] | \] | ||
++++| | ++++| | ||
- | Add 6k to solution, we obtain a solution. | + | Add 6k to solution, we obtain a solution. \\ |
- | Find solutions in set $\{0,1,2,3,4,5\}$ | + | Find solutions in set $\{0,1,2,3,4,5\}$. \\ |
- | Resulting relation for $F(z)$ is $\{ 6k + 5 \mid k \in \mathbb{Z} \}$ | + | Resulting relation for $F(z)$ is $\{ 6k + 5 \mid k \in \mathbb{N} \}$. \\ |
+ | |||
+ | Representation as quantifier-free formula. \\ | ||
+ | |||
+ | Representation as a regular language. | ||
++++ | ++++ | ||
- | We need a nice //representation// of relations | + | ===== Basic Idea ===== |
+ | |||
+ | We come up with a 'nice' //representation// of relations | ||
* in quantifier elimination these are particular quantifier-free formulas | * in quantifier elimination these are particular quantifier-free formulas | ||
* in automata-based methods that we will look at, we represent relations as regular languages | * in automata-based methods that we will look at, we represent relations as regular languages |