6 Interval Temporal Algebra

Interval Temporal Algebra [Slide 23]

(K,ω) is an interval temporal algebra iff

Let skip ≜∼(Σ ∪∼Σ ⋅∼Σ),    finite ≜∼(T ⋅∅) and a ≜∼(finite ⋅∼a)

P1

(K,ω) is a Boolean left (lazy) omega algebra

P2

a ⋅ (b ∪c) ⊆a ⋅b ∪a ⋅c

P3

(skip ∩a) ⋅c ∩ (skip ∩b) ⋅d = (skip ∩a ∩b) ⋅ (c ∩d)

P4

c ⋅ (skip ∩a) ∩d ⋅ (skip ∩b) = (c ∩d) ⋅ (skip ∩a ∩b)

P5

(Σ ∩a) ⋅c ∩ (Σ ∩b) ⋅d = (Σ ∩a ∩b) ⋅ (c ∩d)

P6

c ⋅ (Σ ∩a) ∩d ⋅ (Σ ∩b) = (c ∩d) ⋅ (Σ ∩a ∩b)

P7

finite ⊆skip∗

P8

∼(skip ⋅∼a) = Σ ∪skip ⋅a

P9

∼(∼a ⋅skip) = Σ ∪a ⋅skip

Axiom/proof system for PITL [Slide 24]

PropAx
All axioms for propositional logic
ChopAssoc
⊢ (f0 ; f1) ; f2 ≡ f0 ; (f1 ; f2)
OrChopImp
⊢ (f0 ∨ f1) ; f2 ⊃ (f0 ; f2) ∨ (f1 ; f2)
ChopOrImp
⊢ f0 ; (f1 ∨ f2) ⊃ (f0 ; f1) ∨ (f0 ; f2)
EmptyChop
⊢ empty ; f1 ≡ f1
ChopEmpty
⊢ f1 ; empty ≡ f1
BiBoxChop
⊢ (f0 ⊃ f1) ∧(f2 ⊃ f3) ⊃ (f0 ; f2) ⊃ (f1 ; f3)
StateImpBi
⊢ p ⊃ p
NextImpWNext
⊢ f0 ⊃ ¬¬f0
SkipAnd
⊢ (skip ∧ f0) ; true ⊃ ¬((skip ∧¬f0) ; true)
BoxInduct
⊢ f0 ∧(f0 ⊃ ¬¬f0) ⊃ f0
ChopStarEqv
⊢ f0∗≡ (empty ∨ ((f0 ∧more) ; f0∗))
ChopStarInduct
⊢ (inf ∧ f0 ∧(f0 ⊃ (f1 ∧fmore) ; f0)) ⊃ f1∗
MP
⊢ f0 ⊃ f1 and ⊢ f0 implies ⊢ f1
BoxGen
⊢ f0 implies ⊢ f0
BiGen
⊢ f0 implies ⊢ f0

Examples of proof in ITA [Slide 25]

Example 1.  

finite ⋅Σ
use a ⋅ Σ = a
=
finite

Example 2.  

(T ⋅∅) ⋅∅
use a ⋅ (b ⋅c) = (a ⋅b) ⋅c
=
T ⋅ (∅⋅∅)
use ∅⋅a = ∅
=
T ⋅∅

ITA vs PITL [Slide 26]

Theorem 3. PITL is an interval temporal algebra

Theorem 4. PITL’s axiom/proof system can be derived from ITA’s axiom system

2024-08-01
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