摘要
设G为n(≥3）阶2连通图，δ≤δ*≤△，对任意x∈V（G）,记D（x)={y|y∈V（G）/{x}，d(x,y)≤2},D*(x)={y|y∈D（x）∪{x}),d(y)<δ*}本文证明：如果|D*（x)|<d(x)，则G中有长至少为min{n,2δ*}的圈。
Let G be a 2-connected graph with n(≥3) vertices and δ≤δ≤△ and for any x∈V(G)we suppose D(x) = {y\y∈V(G)\{x},d(x, y)≤2} and D*(x) = {y\y∈(D(x)∪{x}), d(y)<δ*} ,ii is proved that if |D*(x)|<d(x), then there will be a cycle in G with a length of min {n,2δ*} at least.
