Geodesic
On the existence of (196,91,42) Hadamard difference sets
Kragujevac Journal of Mathematics, Tome 34 (2010), p. 113 .

Voir la notice de l'article provenant de la source eLibrary of Mathematical Institute of the Serbian Academy of Sciences and Arts

We use group representations and factorization in the cyclotomic rings to show that $(196, 91, 42)$ Hadamard difference sets exist only in group $(C_7 \times C_7)\rtimes C_4$ with Gap location number $[196, 8]$. We also show that $(980,89,8)$ difference sets may only exist in four groups of order $980$.
Classification : 05B10 05B20
Keywords: Representation, Idempotents, Menon-Hadamard difference Sets, Intersection numbers 
@article{KJM_2010_34_a9,
     author = {Adegoke S. A. Osifodunrin},
     title = {On the existence of (196,91,42) {Hadamard} difference sets},
     journal = {Kragujevac Journal of Mathematics},
     pages = {113 },
     publisher = {mathdoc},
     volume = {34},
     year = {2010},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/KJM_2010_34_a9/}
}
TY  - JOUR
AU  - Adegoke S. A. Osifodunrin
TI  - On the existence of (196,91,42) Hadamard difference sets
JO  - Kragujevac Journal of Mathematics
PY  - 2010
SP  - 113 
VL  - 34
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/KJM_2010_34_a9/
LA  - en
ID  - KJM_2010_34_a9
ER  - 
%0 Journal Article
%A Adegoke S. A. Osifodunrin
%T On the existence of (196,91,42) Hadamard difference sets
%J Kragujevac Journal of Mathematics
%D 2010
%P 113 
%V 34
%I mathdoc
%U http://geodesic.mathdoc.fr/item/KJM_2010_34_a9/
%G en
%F KJM_2010_34_a9
Adegoke S. A. Osifodunrin. On the existence of (196,91,42) Hadamard difference sets. Kragujevac Journal of Mathematics, Tome 34 (2010), p. 113 . http://geodesic.mathdoc.fr/item/KJM_2010_34_a9/