  We consider random sub-graphs of a fixed graph $G=(V,E)$ with large minimum
degree. We fix a positive integer $k$ and let $G_k$ be the random sub-graph
where each $v\in V$ independently chooses $k$ random neighbors, making $kn$
edges in all. When the minimum degree $\delta(G)\geq
(\frac12+\epsilon)n,\,n=|V|$ then $G_k$ is $k$-connected w.h.p. for $k=O(1)$;
Hamiltonian for $k$ sufficiently large. When $\delta(G) \geq m$, then $G_k$ has
a cycle of length $(1-\epsilon)m$ for $k\geq k_\epsilon$. By w.h.p. we mean
that the probability of non-occurrence can be bounded by a function $\phi(n)$
(or $\phi(m)$) where $\lim_{n\to\infty}\phi(n)=0$.
