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)
Variations on a scheme of McFarland for noncyclic difference sets. (English) Zbl 0583.05016
The author observes that the construction for difference sets due to R. L. McFarland [J. Comb. Theory, Ser. A 15, 1–10 (1973; Zbl 0268.05011)] can be extended to a much larger class of groups and that many more inequivalent difference sets can be produced in some of the same groups. A special case of a new result enables the author to obtain Hadamard difference sets in all groups 2 s × 2 s+2 . These difference sets (in abelian groups of order 2 2s+2 and exponent 2 s+2 ) demonstrate the sharpness of the exponent bound established by R. J. Turyn [Pac. J. Math. 15, 319–346 (1965; Zbl 0135.05403)]. Using the new general construction, the author also produces difference sets in ten of the fourteen groups of order 16 and proves that the cyclic and dihedral groups are the only groups of order 16 which do not contain a nontrivial difference set. Details of the results presented in this interesting paper are difficult to describe in a limited space.
Reviewer: H.P.Yap

MSC:
05B10Difference sets
05B05Block designs (combinatorics)
20D60Arithmetic and combinatorial problems on finite groups
20K01Finite abelian groups