zbMATH — the first resource for mathematics

Examples
Geometry Search for the term Geometry in any field. Queries are case-independent.
Funct* Wildcard queries are specified by * (e.g. functions, functorial, etc.). Otherwise the search is exact.
"Topological group" Phrases (multi-words) should be set in "straight quotation marks".
au: Bourbaki & ti: Algebra Search for author and title. The and-operator & is default and can be omitted.
Chebyshev | Tschebyscheff The or-operator | allows to search for Chebyshev or Tschebyscheff.
"Quasi* map*" py: 1989 The resulting documents have publication year 1989.
so: Eur* J* Mat* Soc* cc: 14 Search for publications in a particular source with a Mathematics Subject Classification code (cc) in 14.
"Partial diff* eq*" ! elliptic The not-operator ! eliminates all results containing the word elliptic.
dt: b & au: Hilbert The document type is set to books; alternatively: j for journal articles, a for book articles.
py: 2000-2015 cc: (94A | 11T) Number ranges are accepted. Terms can be grouped within (parentheses).
la: chinese Find documents in a given language. ISO 639-1 language codes can also be used.

Operators
a & b logic and
a | b logic or
!ab logic not
abc* right wildcard
"ab c" phrase
(ab c) parentheses
Fields
any anywhere an internal document identifier
au author, editor ai internal author identifier
ti title la language
so source ab review, abstract
py publication year rv reviewer
cc MSC code ut uncontrolled term
dt document type (j: journal article; b: book; a: book article)
Planar functions, relative difference sets, and character theory. (English) Zbl 0865.05020
Let H and K be groups of order n. A mapping f from H to K is called a planar function of degree n if for each hH-{1}, the induced mapping f h :xf(hx)f(x) -1 is bijective. It is known that a planar function exists if and only if there exists an (n,n,n,1)-relative difference set in H×K relative to {1}×K. The author uses character theory to prove new results on the existence of planar functions from Z n to Z n and for the corresponding relative difference sets. In particular, the author shows that there are no planar functions from Z pq to Z pq where p and q are any primes and that except for 4 undecided cases, there is no planar function from Z n to Z n if n is not a prime and n50,000.
MSC:
05B10Difference sets