NECESSARY AND SUFFICIENT CONDITIONS FOR A SPACE TO HAVE A MAXIMAL, PROPER, DENSE, NORMAL T0 OR A T4 SUBSPACE
Necessary and sufficient conditions for a space to have a maximal, proper, dense, normal T0 or a maximal, proper, dense, T4 subspace are found which motivates the introduction of a new topological property.
proper subspaces, dense subspaces, maximal subspaces, normal.