delkspansjon
Delkspansjon is a term used in mathematics, specifically in the context of linear algebra and module theory. It refers to a way of decomposing a module into a direct sum of submodules. A module M is said to have a delkspansjon if it can be written as M = M1 + M2 + ... + Mn, where each Mi is a submodule of M, and for any selection of elements m1 from M1, m2 from M2, ..., mn from Mn, if their sum is zero (m1 + m2 + ... + mn = 0), then each mi must be zero. This condition implies that the intersection of any submodule Mi with the sum of the other submodules is trivial. In simpler terms, a delkspansjon is a decomposition where each component submodule contributes uniquely to the overall structure of the module, with no overlap in their contributions. This concept is analogous to a direct sum of vector spaces in linear algebra. The existence and nature of delkspansjoner are important for understanding the structure of modules, particularly for modules over rings that are not necessarily fields. Studying these decompositions can reveal properties of the module that might not be apparent from considering it as a whole.