Chains of congruences on a completely 0-simple semigroup
G. B. Preston · Journal of the Australian Mathematical Society · 1965
Let ρ and σ be two congruences on a completely 0-simple semigroup. Suppose that there is a maximal chain of congruences from ρ to σ which is of finite length. Then, as we shall show, any maximal chain of congruences from ρ to σ finite and of the same length.