Cryotank In science fiction, cryogenic tanks are used to freeze people. "cry-" is a Greek prefix which means "cold or freezing", hence humans are stored in the tank frozen until a future date. Cryotanks are found in some science fiction films such as "Prometheus" (2012) and "The Host" (2013). Cryotank Cryotank or cryogenic tank is a tank that is used to store frozen biological material. The term “cryotank” refers to storage of super-cold fuels, such as liquid oxygen and liquid hydrogen. Cryotanks and cryogenics can be seen in many sci-fi movies, but they are still currently undeveloped. All that needs to
Prefix grammar Prefix grammar In theoretical computer science and formal language theory, a prefix grammar is a type of string rewriting system, consisting of a set of string rewriting rules, and similar to a formal grammar or a semi-Thue system. What is specific about prefix grammars is not the shape of their rules, but the way in which they are applied: only prefixes are rewritten. The prefix grammars describe exactly all regular languages. A prefix grammar "G" is a 3-tuple, (Σ, "S", "P"), where For strings "x", "y", we write "x" → "y" (and say: "G" can derive "y" from "x" in