The Hadamard circulant conjecture
arXiv:1109.0748 · doi:10.1112/blms/bdq112
Abstract
It is shown that if is a circulant Hadamard $4n\ti 4n $ then . This proves the Hadamard circulant conjecture.
This is post publication revision of on-line Bull. London Math. Soc. version which changes subsection 3.3