4
Ric
(
x,y
) =
{
Ric
(
x
+
y,x
+
y
)
-
Ric
(
x,x
)
-
Ric
(
y,y
)
}
.
{Ric(x + y,x + y) - Ric(x,x) - Ric(y,y)}.{Ric(x + y,x + y) - Ric(x,x) - Ric(y,y)}.