On the arithmetic of arithmetical congruence monoids

• Autorzy: M. Banister , J. Chaika , S. T. Chapman , W. Meyerson
• Języki publikacji: EN

Abstrakty

EN

Let ℕ represent the positive integers and ℕ₀ the non-negative integers. If b ∈ ℕ and Γ is a multiplicatively closed subset of $ℤ_b = ℤ/bℤ$, then the set $H_Γ = {x ∈ ℕ | x + bℤ ∈ Γ} ∪ {1}$ is a multiplicative submonoid of ℕ known as a congruence monoid. An arithmetical congruence monoid (or ACM) is a congruence monoid where Γ = ā consists of a single element. If $H_Γ$ is an ACM, then we represent it with the notation M(a,b) = (a + bℕ₀) ∪ {1}, where a, b ∈ ℕ and a² ≡ a (mod b). A classical 1954 result of James and Niven implies that the only ACM which admits unique factorization of elements into products of irreducibles is M(1,2) = M(3,2). In this paper, we examine further factorization properties of ACMs. We find necessary and sufficient conditions for an ACM M(a,b) to be half-factorial (i.e., lengths of irreducible factorizations of an element remain constant) and further determine conditions for M(a,b) to have finite elasticity. When the elasticity of M(a,b) is finite, we produce a formula to compute it. Among our remaining results, we show that the elasticity of an ACM M(a,b) may not be accepted and show that if an ACM M(a,b) has infinite elasticity, then it is not fully elastic.

Kategorie tematyczne

• 20D60: Arithmetic and combinatorial problems
• 20M14: Commutative semigroups
• 13F05: Dedekind, Pr\"ufer, Krull and Mori rings and their generalizations

• Wydawca: Institute of Mathematics Polish Academy of Sciences
• Czasopismo: Colloquium Mathematicum
• Rocznik: 2007
• Tom: 108
• Numer: 1
• Strony: 105-118

Daty

wydano

2007

Twórcy

autor

M. Banister

• Department of Mathematics, Harvey Mudd College, 1250 N. Dartmouth Ave., Claremont, CA 91711, U.S.A.
• Department of Mathematics, University of California at Santa Barbara, Santa Barbara, CA 93106, U.S.A.

autor

J. Chaika

• Department of Mathematics, The University of Iowa, 14 MacLean Hall, Iowa City, IA 52242, U.S.A.
• Mathematics Department, MS 136, Rice University, 6100 S. Main St., Houston, TX 77005-1892, U.S.A.

autor

S. T. Chapman

• Department of Mathematics, Trinity University, One Trinity Place, San Antonio, TX 78212-7200, U.S.A.

autor

W. Meyerson

• Department of Mathematics, Harvard University, One Oxford Street, Cambridge, MA 02138, U.S.A.
• Mathematics Department, University of California at Los Angeles, Box 951555, Los Angeles, CA 90095-1555, U.S.A

Identyfikatory

DOI

10.4064/cm108-1-9