The adcending chain condition for real ideas.
If is a commutative ring with identity and is defined by letting mean or , then is a partially ordered ring. Necessary and sufficient conditions on are given for to be a lattice, and conditions are given for it to be modular or distributive. The results are applied to the rings of integers mod for . In particular, if is reduced, then is a lattice iff is a weak Baer ring, and is a distributive lattice iff is a Boolean ring, , , or a four element field.
We give a description of faces, of all codimensions, for the cones spanned by the set of weights associated to the rings of semi-invariants of quivers. For a triple flag quiver and its faces of codimension 1 this description reduces to the result of Knutson-Tao-Woodward on the facets of the Klyachko cone. We give new applications to Littlewood-Richardson coefficients, including a product formula for LR-coefficients corresponding to triples of partitions lying on a wall of the Klyachko cone. We systematically...
Different properties of rings and fields are discussed [12], [41] and [17]. We introduce ring homomorphisms, their kernels and images, and prove the First Isomorphism Theorem, namely that for a homomorphism f : R → S we have R/ker(f) ≅ Im(f). Then we define prime and irreducible elements and show that every principal ideal domain is factorial. Finally we show that polynomial rings over fields are Euclidean and hence also factorial