Let G be a finite simple graph. A G-design (G-packing design, G-covering design) of λKv, denoted by (v, G,λ)-GD ((v, G, λ)-PD, (v, G,λ)-CD), is a pair (X,B) where X is the vertex set of Kv and B is a collection of...Let G be a finite simple graph. A G-design (G-packing design, G-covering design) of λKv, denoted by (v, G,λ)-GD ((v, G, λ)-PD, (v, G,λ)-CD), is a pair (X,B) where X is the vertex set of Kv and B is a collection of subgraphs of Kv, called blocks, such that each block is isomorphic to G and any two distinct vertices in Kv are joined in exactly (at most, at least) λ blocks of B. A packing (covering) design is said to be maximum (minimum) if no other such packing (covering) design has more (fewer) blocks. In this paper, we determine the existence spectrum for the K2,3-designs of λKv,λ> 1, and construct the maximum packing designs and the minimum covering designs of λKv with K2,3 for any integer λ.展开更多
文摘Let G be a finite simple graph. A G-design (G-packing design, G-covering design) of λKv, denoted by (v, G,λ)-GD ((v, G, λ)-PD, (v, G,λ)-CD), is a pair (X,B) where X is the vertex set of Kv and B is a collection of subgraphs of Kv, called blocks, such that each block is isomorphic to G and any two distinct vertices in Kv are joined in exactly (at most, at least) λ blocks of B. A packing (covering) design is said to be maximum (minimum) if no other such packing (covering) design has more (fewer) blocks. In this paper, we determine the existence spectrum for the K2,3-designs of λKv,λ> 1, and construct the maximum packing designs and the minimum covering designs of λKv with K2,3 for any integer λ.
