On GCD-morphic sequences

Abstract

This note is a response to one of the problems posed by Kwaśniewski in [1,2], see also [3] i.e. GCD-morphic Problem III. We show that any GCD-morphic sequence $F$ is at the point product of primary GCD-morphic sequences and any GCD-morphic sequence is encoded by natural number valued sequence satisfying condition (C1). The problem of general importance - for example in number theory was formulated in [1,2] while investigating a new class of DAG's and their correspondent p.o. sets encoded uniquely by sequences with combinatorially interpretable properties.