A theorem of single-sorted algebra states that, for a closure space and a natural number , the closure operator on the set is -ary if, and only if, there exists a single-sorted signature and a -algebra such that every operation of is of an arity and , where is the subalgebra generating operator on determined by . On the other hand, a theorem of Tarski asserts that if is an -ary closure operator on a set with , and if with , , where is the set of all natural numbers such that has an irredundant basis ( minimal generating set) of elements, such that ${i+1,\ldots, j-1}\cap (A,J) = \varnothingj-i\leq n-1$. In this article we state and prove the many-sorted counterparts of the above theorems. But, we remark, regarding the first one under an additional condition: the uniformity of the many-sorted closure operator.

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