Projective planes I

Semiadditive rings are defined and their relationship with the projective planes is studied. Free semiadditive rings provide an analogue of the ring of integers and polynomials for the ternary rings. A structure theory for free semiadditive rings is developed. It is shown that each element of a large class of semiadditive rings is obtained from a quotient of a polynomial ring over integers by an additive subgroup, by twisting addition and multiplication. This class includes all planar ternary rings. These methods are being developed to study the well known conjectures that every finite projective plane with no proper subplane is isomorphic to a prime field plane and that the order of a finite projective plane is a power of a prime number. Applications to these problems will be discussed in part II.