NEW RESTRICTIONS ON SPATIAL TOPOLOGY OF THE UNIVERSE FROM MICROWAVE BACKGROUND TEMPERATURE-FLUCTUATIONS

If the Universe has the topology of a 3-torus (T3), then it follows from recent data on the large-scale temperature fluctuations, DELTAT/T, of the cosmic microwave background that either the minimal size of the torus is at least on the order of the present cosmological horizon or the large-scale DELTAT/T pattern should have a symmetry plane (in the case of the effective T1 topology), or a symmetry axis (in the case of the effective T2 topology). The latter possibility can probably be ruled out by the data.