### 7.1 Equations, polarized T^{3}-Gowdy

In the case of polarized Gowdy, , so that Equations (16) – (19) reduce to
As an aside, it is of interest to note that the set coincides with the image of a geodesic in
hyperbolic space . This system of equations should be compared with (11a) – (11d) of [50] (note,
however, that the variables of [50] are somewhat different).