Optimal (v, 4, 2, 1) optical orthogonal codes (OOC) with v <= 75 and v = 71 are classified up to equivalence. One (v, 4, 2, 1) OOC is presented for all v ≤ 181, for which an optimal OOC exists.
A parallelism in $$PG(n,q)$$ P G ( n , q ) is transitive if it has an automorphism group which is transitive on the spreads. A parallelism is regular if all its spreads are regular. In $$PG(3,4)$$ P G ( 3 , 4 ) no examples of transitive and no regular parallelisms are known. Transitive parallelisms in $$PG(3,4)$$ P G ( 3 , 4 ) must have automorphisms of… (More)
We classify up to multiplier equivalence optimal (v, 3, 1) binary cyclically permutable constant weight (CPCW) codes with v ≤ 61. There is a one-to-one correspondence between optimal (v, 3, 1) CPCW codes, optimal cyclic binary constant weight codes with weight 3 and minimal distance 4, (v, 3; (v − 1)/6) difference packings, and optimal (v, 3, 1) optical… (More)