It is shown that for a definite cluster in the two-dimensional U=∞ Hubbard model, there are states in any ${\mathit{S}}^{\mathit{z}}$ sector, which are degenerate with the lowest state in the ${\mathit{S}}_{\max }^{\mathit{z}}$ sector. It is shown further that these states become the lowest ones in their sectors as the cluster becomes large enough, keeping the hole concentration constant. Then degenerate ground states of various ${\mathit{S}}^{\mathit{z}}$ are obtained. The properties of the ground state of any ${\mathit{S}}^{\mathit{z}}$<${\mathit{S}}_{\max }^{\mathit{z}}$ can be found through those of the ground state of ${\mathit{S}}_{\max }^{\mathit{z}}$.

• Received 12 January 1994

DOI:https://doi.org/10.1103/PhysRevB.51.1435