Radiation-vacuum density equality ($1+z_{r\Lambda }=({\Omega }_{\Lambda 0}/{\Omega }_{r0}{)}^{1/4}$)

The equality of a radiation density proportional to $(1+z{)}^4$ and a constant vacuum density. It is only a crossing of two components. Matter can dominate both at this epoch, so radiation-vacuum equality need not mark a change in the universe's dominant component.