CTL* Semantics

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CTL Semantics

• CS 586

2
E Exists a path
s
NOT a model of
3
E Exists a path
s
4
A All paths
s
NOT a model of
5
A All paths
s
6
F Eventually
s
7
EF Along some path, eventually
s
NOT a well-formed problem
8
AF Along every path, eventually
s
NOT a model of
9
AF Along every path, eventually
s
10
EGAF
s
there exists a path, on which it is always true
that
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EGAF
s
there exists a path, on which it is always true
that For all paths, eventually red.
12
EGAF
always means true for all states on the
path. Get AF red for s.
s
there exists a path, on which it is always true
that For all paths, eventually red.
13
EGAF
always means true for all states on the
path. Get AF red for s.
s
there exists a path, on which it is always true
that For all paths, eventually red.
14
EGAF
always means true for all states on the
path. Get AF red for s. Get AF red for t.
s
there exists a path, on which it is always true
that For all paths, eventually red.
t
15
EGAF
always means true for all states on the
path. Get AF red for s. Get AF red for t. Get
AF red for u.
s
there exists a path, on which it is always true
that For all paths, eventually red.
t
u
16
EGAF
always means true for all states on the
path. Get AF red for s. Get AF red for t. Get
AF red for u. Get AF red for v.
s
there exists a path, on which it is always true
that For all paths, eventually red.
t
u
v
17
s
18
Some Examples

• It always gets cloudy before it rains
• Bad things never happen
• Its possible to have your cake and eat it too.
• I will eventually grade your homework