Finite semifields and projective planes

• Main Author: Knuth, Donald Ervin
• Format: Others
• Published: 1963
• Online Access: https://thesis.library.caltech.edu/2441/1/Knuth_de_1963.pdf; Knuth, Donald Ervin (1963) Finite semifields and projective planes. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/T3Q6-JC64. https://resolver.caltech.edu/CaltechETD:etd-06042004-141331 <https://resolver.caltech.edu/CaltechETD:etd-06042004-141331>

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. This paper makes contributions to the structure theory of finite semifields, i.e., of finite nonassociative division algebras with unit. It is shown that a semifield may be conveniently represented as a 3-dimensional array of numbers, and that matrix multiplications applied to each of the three dimensions correspond to the concept of isotopy. The six permutations of three coordinates yield a new way to obtain projective planes from a given plane. Several new classes of semifields are constructed; in particular one class, called the binary semifields, provides an affirmative answer to the conjecture that there exist non-Desarguesian projective planes of all orders 2[...], if n is greater than 3. With the advent of binary semifields, the gap between necessary and sufficient conditions on the possible orders of semifields has disappeared.