AGV 1.3 -- The Logic-Automata Connection
Previous chapter: Synthesis
This is a learning note of a course in CISPA, UdS. Taught by Bernd Finkbeiner
Verification or Synthesis
In applications like verification and synthesis, the automata- and game-theoretic machinery is usually “hidden” behind a logical formulation of the problem.
Logics with corresponding Automata
S1S‘s expressiveness exceeds that of LTL, and
S2S‘s expressiveness exceeds that of CTL* (on binary trees)
Logic | Usage | Example |
---|---|---|
Linear-time temporal logic (LTL) | sets of infinite words | $\square \Diamond \ell_1$ |
Computation-tree logic (CTL / CTL*) | sets of infinite trees | $\textsf{EF}\ell_1 \wedge \textsf{EF}m_1$ |
Monadic second-order logic with one successor (S1S) | logic over infinite words | $\forall x . x \in P \rightarrow S(x) \in P$ |
Monadic second-order logic with two successors (S2S) | logic over infinite binary trees | $\forall x . x \in P \rightarrow S_1(x) \in P \vee S_2(x) \in P$ |
Explaination
- $\square \Diamond \ell_1$
$P_0$ is infinitely often at location $\ell_1$. - $\textsf{EF}\ell_1 \wedge \textsf{EF}m_1$
There exists a computation path in which $P_0$ reaches location $\ell_1$, and
there is a (possibly different) computation path in which $P_1$ reaches location $m_1$. - $\forall x . x \in P \rightarrow S(x) \in P$
A (given) set of natural numbers $P$ is either empty, or
consists of all positions starting from some position of the word. - $\forall x . x \in P \rightarrow S_1(x) \in P \vee S_2(x) \in P$
A (given) set of nodes $P$ contains from each node $n \in P$ an entire path starting in $n$.