Skip to main content
5 of 5
edited tags
kodlu
  • 10.4k
  • 2
  • 36
  • 55

One question on circulant $\pm1$ matrices

Let $n > 13$ be a positive integer. Is there any $n \times n$ circulant $\pm1$ matrix $A$ satisfying the following property

$$AA^T=(n-1)I+J$$

where $I$ is the $n \times n$ identity matrix and $J$ is the $n\times n$ matrix of ones?

I conjecture that the answer is no. But I can't prove it.

user369335
  • 696
  • 1
  • 5
  • 22