Information Technology Reference
In-Depth Information
2.12.2
Syntax of dynamic description logic
Dynamic description logic DDL is formed through extending traditional
description logic (Shi, et al. 2005), while traditional description logic has many
species. The dynamic description logic DDL studied here is based on description
logic ALC.
Definition 2.27
The primitive symbols in DDL are:
· concept names:
C
1
,
C
2
, …;
· role names:
R
1
,
R
2
, …;
· individual constant:
a
,
b
,
c
, …;
· individual variable: x, y, z, …;
· concept operator: ¬,
ե
,
զ
and quantifier ∃, ∀;
· formula operator: ¬,
Ӽ
, → and quantifier ∀;
· action names:
A
1
,
A
2
, …;
· action constructs: ;(sequence),
֖
(choice), *(iteration), ?(test);
· action variable:
,
, …;
· formula variable:
ϕ
,
ɂ
,
ʩ
, …;
· state variable:
u
,
v
,
w
, …
.
Definition 2.28
Concepts in DDL are defined as follows:
(1) Primitive concept P, top
⊥
and bottom
⊥
are concepts;
(2) If C and D are concepts, then ¬C, C
∩
D, and C
∪
D are concepts;
∃
R.C and
∀
R.C are concepts;
(3) If C is concept and R is role, then
(4) If C is concept and
is action, then [
]C is action too.
