Let f be a complex-valued function on a finite field F such that f(0)=0, f(1)=1, and |f(x)|=1 for x ] 0. H. Cohn asked if it follows that f is a nontrivial multiplicative character provided that ; x Β₯ F f(x) f(x+h)=-1 for h ] 0. We prove that this is the case for finite fields of prime cardinality u
On a Problem of H. Cohn for Character Sums
β Scribed by Todd Cochrane; David Garth; Zhiyong Zheng
- Publisher
- Elsevier Science
- Year
- 2000
- Tongue
- English
- Weight
- 141 KB
- Volume
- 81
- Category
- Article
- ISSN
- 0022-314X
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β¦ Synopsis
Cohn's problem on character sums (see , p. 202) asks whether a multiplicative character on a finite field can be characterized by a kind of two level autocorrelation property. Let f be a map from a finite field F to the complex plane such that f (0)=0, f (1)=1, and | f (:)| =1 for all :{0. In this paper we show that if for all a, b # F*, we have (q&1) :
then f is a multiplicative character of F. We also prove that if F is a prime field and f is a real valued function on F with f (0)=0, f (1)=1, and | f (:)| =1 for all :{0, then : # F f (:) f (:+a)=&1 for all a{0 if and only if f is the Legendre symbol.
These results partially answer Cohn's problem.
π SIMILAR VOLUMES
We prove some partial results concerning the following problem: Assume that F is a finite field, a i is a complex number for each i # F such that a 0 =0, a 1 =1, |a i | =1 for all i # F "[0], and i # F a i+j aΓ i =&1 for all i # F "[0]. Does it follow that the function i Γ a i is a multiplicative ch
The existence and uniqueness of a weak solution of a Neumann problem is discussed for a second-order quasilinear elliptic equation in a divergence form. The note is a continuation of a recent paper, where mixed boundary value problems were considered, which guaranteed the coerciveness of the problem