Historically hashes have been from a large set (say 256 characters) to a smaller set (256 bits).
Also, hash functions that are P-complete have no known parallel algorithm; they must be computed serially which ensures a certain amount of temporal cost in computing them.
Three questions:
What is the technical term for hashes that map to a larger set than the domain?
Are there any good P-complete hashes?
Are there any good P-complete hashes that map to a larger set?