Interval Relation
Equivalent Relations on Endpoints
ts
t+ < s(tS-) & (t+
s+)
t overlaps s
(t- <s-) & (t+ ) s-) & (i+ <s+)
t meets s
tt = St during s
((t-> s-) & (t+ =( S+)) or
(it- >= S-) & (t+ < .$+)
Figure 1: Interval Relation Defined by Endpoints
Relation
Symbol Symbol for
Inverse
Pictoral Example
<
>
X before Y X equal Y
XXX YYY XXX YYY
X meets Y
mi
XXXYYY
X overlaps Y
0
oi
XXX YYY
X during Y
d
di
XXX YYYYYY
X starts Y
S
si
XXX YYYYY
X finishes Y
f
fi
XXX YYYYY
Figure 2: The Thirteen Possible Relationsliips
Network Representation Ni --(d)→ Nj Ni --(< d di)- Nj
Relation 1. i during i 2, i during j or
i before j or
j during i 3. (i<j) or (i >j) or
i meets j or j meets i
N; --<< > m mi) - N;
Figure 3: Representing Knowledge of Temporal Relations in a Network