Observational relations in model universes dominated by domain-wall-like matter

In model universes dominated by defected matter such as domain walls, we consider observational relations among apparent magnitudes of galaxies, redshifts and number counts. It is shown that the ratio of the mean negative pressure to the mean density plays a role similar to the positive cosmological constant, and that the domain-wall-dominated model may be consistent with the recent number count observations. (author)