Vacuum packing preventing the evaporation of volatile components. It is also commonly used to store dry foods over a long period of time, such as cereals, nuts, cured meats, cheese, smoked fish, coffee, and potato chips (crisps). On a more short term basis, vacuum packing can also be used to store fresh foods, such as vegetables, meats, and liquids, because it inhibits bacterial growth. Vacuum packing greatly reduces the bulk of non-food items. For example, clothing and bedding can be stored in bags evacuated with a domestic vacuum cleaner or a dedicated vacuum sealer. This technique is sometimes used to compact household
Packing in a hypergraph that the achievable packing by the Rödl nibble is in some sense close to that of the random greedy algorithm. The problem of finding the number of such subsets in a "k"-uniform hypergraph was originally motivated through a conjecture by Paul Erdős and Haim Hanani in 1963. Vojtěch Rödl proved their conjecture asymptotically under certain conditions in 1985. Pippenger and Joel Spencer generalized Rödl's results using a random greedy algorithm in 1989. In the following definitions, the hypergraph is denoted by "H"=("V","E"). "H" is called a "k"-uniform hypergraph if every edge in "E" consists of exactly "k" vertices. formula_1 is