*Article* **Polyadic Analogs of Direct Product**

**Steven Duplij**

> Center for Information Technology (WWU IT), Universität Münster, Röntgenstrasse 7-13, 48149 Münster, Germany; douplii@uni-muenster.de

**Abstract:** We propose a generalization of the external direct product concept to polyadic algebraic structures which introduces novel properties in two ways: the arity of the product can differ from that of the constituents, and the elements from different multipliers can be "entangled" such that the product is no longer componentwise. The main property which we want to preserve is associativity, which is gained by using the associativity quiver technique, which was provided previously. For polyadic semigroups and groups we introduce two external products: (1) the iterated direct product, which is componentwise but can have an arity that is different from the multipliers and (2) the hetero product (power), which is noncomponentwise and constructed by analogy with the heteromorphism concept introduced earlier. We show in which cases the product of polyadic groups can itself be a polyadic group. In the same way, the external product of polyadic rings and fields is generalized. The most exotic case is the external product of polyadic fields, which can be a polyadic field (as opposed to the binary fields), in which all multipliers are zeroless fields. Many illustrative concrete examples are presented.

**Keywords:** direct product; direct power; polyadic semigroup; arity; polyadic ring; polyadic field

**MSC:** 16T25; 17A42; 20B30; 20F36; 20M17; 20N15
