Abstract
A subspace of F2n is called cyclically covering if every vector in F2n has a cyclic shift which is inside the subspace. Let h2(n) denote the largest possible codimension of a cyclically covering subspace of F2n. We show that h2(p)=2 for every prime p such that 2 is a primitive root modulo p, which, assuming Artin's conjecture, answers a question of Peter Cameron from 1991. We also prove various bounds on h2(ab) depending on h2(a) and h2(b) and extend some of our results to a more general set-up proposed by Cameron, Ellis and Raynaud.
Original language | English |
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Article number | 105436 |
Journal | Journal of Combinatorial Theory. Series A |
Volume | 181 |
DOIs | |
Publication status | Published - 2021 |
Externally published | Yes |
Keywords
- Cyclic shift
- Cyclically covering subspaces
- Isbell's conjecture
- Smallest codimension