Database Reference
In-Depth Information
p
i
]
E
.
The solution of
p
1
is the following tree (note that here we are using only the
binary operators '
It is easy to verify that for each
p
i
,
{
p
i
,
s
E
(p
i
)
}⊆[
2
', that is, '
3
'):
', instead of the unique operator '
3
' as a finite 3-ary coproduct operator (analogous to
Alternatively, if we consider '
+
3
' in the guarded system of equations) then we obtain a very simple tree
'
n
',
n
that is similar to the transition tree if instead of the nodes '
+
≥
2, we use the
states of a transition system, and instead of the unary nodes '
a
_' we use the
a
-labeled edges that finish with another state, as we will see in the next section for
the operational semantics of database-mapping process-programs. Note that if we
simplify the family of action-prefixing unary operators '
a.
_' by the binary connec-
tive '
.
' then we would obtain the following tree with leafs in
Act
:
⊗
