2 GeoMTGM
27
( T n (m) = geoComplex ∧
( T n (n) = atomic ∨ T n (n) = stream ∨ T n (n) = geoAtomic)))
4. “Has Property” Edges. Each atomic node is connected to its parent by an edge
labeled “Has Property” and with temporal element I.
∀∀m, label, n ∈ E
(( T n (m) = complex ∨
T n (m) = geoComplex) ∧
T n (n) = atomic) →
label = relational, “HasProperty, ” ⊥, ⊥, II
5. “HasMMProperty” Edges. Each stream node is connected to its parent by a
relational edge with label formed by the name “HasMMProperty,” the temporal
element I, and the value value p that specifies the subpart of the media object.
∀∀m, label, n ∈ E
(( T n (m) = complex ∨
T n (m) = geoComplex) ∧
T n (n) = stream)
→ label = relational, “HasMMProperty, ” value p , ⊥, II
6. “HasGeoProperty” Edges. Each geographical atomic node is connected to its
parent by an edge labeled “HasGeoProperty” and with temporal element I.
∀∀m, label, n ∈ E
( T n (m) = geoComplex) ∧
T n (n) = geoAtomic) →
label = relational, “HasGeoProperty, ” ⊥, ⊥, II
7. Uniqueness of Edges. At a specific time instant, at most one edge with a specific
name RelName can exist between two nodes. This is due to the fact that an edge
represents a relationship between two nodes; thus it makes no sense to represent
the same relationship with two edges.
∀∀m,relational, RelName, I 1 , n ∈ E
(m, relational, RelName, I 2 , n ∈ E (I 1 ∩ I 2 ∅))
8. Temporal Elements. Temporal elements are not associated to atomic, stream, and
geoAtomic nodes, because in the database the temporal element of a value coincides with the temporal element of its ingoing edge.
∀x ∈ N(( T n (x) = atomic ∨
T n (x) = stream ∨
T n (x) = geoAtomic) → V (x) = ⊥)