<s>
In	O
relational	B-Algorithm
algebra	I-Algorithm
,	O
a	O
rename	B-Algorithm
is	O
a	O
unary	O
operation	O
written	O
as	O
where	O
:	O
</s>
<s>
The	O
result	O
is	O
identical	O
to	O
except	O
that	O
the	O
attribute	O
in	O
all	O
tuples	B-Application
is	O
renamed	O
to	O
.	O
</s>
<s>
For	O
an	O
example	O
,	O
consider	O
the	O
following	O
invocation	O
of	O
on	O
an	O
relation	B-Algorithm
and	O
the	O
result	O
of	O
that	O
invocation	O
:	O
</s>
<s>
Formally	O
,	O
the	O
semantics	O
of	O
the	O
rename	B-Algorithm
operator	O
is	O
defined	O
as	O
follows	O
:	O
</s>
<s>
where	O
is	O
defined	O
as	O
the	O
tuple	B-Application
,	O
with	O
the	O
attribute	O
renamed	O
to	O
,	O
so	O
that	O
:	O
</s>
