ScienceAsia 27 (2001) : 199-202 Arithmetic Functions and Operators Vichian Laohakosola, Nittiya Pabhapoteb,* and Nalinee Wechwiriyakulb a Department of Mathematics, Kasetsart University, Bangkok 10900, Thailand. b Department of Mathematics, The University of the Thai Chamber of Commerce, Bangkok 10400, Thailand * Corresponding author, E-mail:
[email protected] Received 22 Dec 1999 Accepted 1 May 2001 ABSTRACT Basic results about arithmetic functions and their major operations, namely, valuation, derivation and operators, are collected. The logarithmic and related operators, introduced and applied in 1968 by D Rearick to establish isomorphisms among various groups of real-valued arithmetic functions are extended to complex-valued arithmetic functions along the original lines suggested by him. KEYWORDS: arithmetic functions, operators. INTRODUCTION A derivation over A7 is a function D : A → A such that for all f, g ∈ A, and for all a, b ∈ C , we An arithmetic function is a function whose have D(f * g) = Df * g + f * Dg, D(af + bg) = aDf + domain is N and range is a subset of C. bDg. Three typical examples of derivation, which Let f and g be arithmetic functions. The sum (or are often used, are addition) of f and g is an arithmetic function f + g (i) log-derivation : Dl f (n) := f (n) log n , defined by (f + g)(n) = f(n) + g(n). The Dirichlet (ii) p-basic derivation (p prime) : Dp f (n) := product ( or convolution or Dirichlet multiplication) f (np) vp(np), where vp(m) denotes the of f and g is an arithmetic function f * g defined by highest power of p dividing m, (iii) Dh f (n) := f(n) h(n), where h is a completely additive arithmetic function, ie, n ()()f ∗=gn∑ fdg()( ).