Samkhan Hobuntud. Linear transformation subsemigroups of Lr(V,W) admitting the structure of a semihyperring with zero. Master's Degree(Mathematics). Chulalongkorn University. Center of Academic Resources. : Chulalongkorn University, 2008.
Linear transformation subsemigroups of Lr(V,W) admitting the structure of a semihyperring with zero
Abstract:
A semihyperring with zero is a triple (𝐴,+,*) such that (𝐴,+) is a semihypergroup, (𝐴,*) is a semigroup, * is distributive over + and there exists 𝑂∊𝐴 (called a zero) such that 𝑥+0=0+𝑥={𝑥} and 𝑥*0=0*𝑥=0 for all 𝑥∊𝐴. For a semigroup 𝑆, let 𝑆⁰ be 𝑆 if S has a zero and 𝑆 contains more than one element; otherwise, let 𝑆⁰ be the semigroup 𝑆 with a zero adjoined. Then 𝑆⁰is a semigroup with zero. We say that a semigroup 𝑆 admits the structure of a semihyperring with zero if there exists a hyperoperation on 𝑆⁰such that (𝑆⁰,+,*) is a semihy- perring with zero 𝑂 where * is the operation on 𝑆⁰ and 𝑂 is the zero of 𝑆⁰.
Let 𝑉 be a vector space over a division ring 𝑅, 𝑊 a subspace of 𝑉 and 𝐿[subscript R](𝑉, 𝑊) the semigroup of all linear transformations from 𝑉 into 𝑊 under composition. For each α∊𝐿[subscript R](𝑉, 𝑊), let 𝐹(α ) consist of all elements in 𝑉 fixed by α. Let 𝑂𝑀[subscript R](𝑉, 𝑊), 𝑂𝐸[subscript R](𝑉, 𝑊), 𝐺[subscript R](𝑉, 𝑊), 𝐴𝐼[subscript R](𝑉, ͟𝑊) and 𝐴𝐼[subscript R](͟𝑉, 𝑊) be as follows:
𝑂𝑀[subscript R](𝑉, 𝑊) = { α∊𝐿[subscript R](𝑉, 𝑊)|dim[subscript R] Kerα=∞},
𝑂𝐸[subscript R](𝑉, 𝑊) = {α∊𝐿[subscript R](𝑉, 𝑊)|dim[subscript R] (𝑊/Imα)=∞},
𝐺[subscript R](𝑉, 𝑊) = { α∊𝐿[subscript R](𝑉, 𝑊)|α|[subscript w] is an iso,orphism},
𝐴𝐼[subscript R](𝑉, ͟𝑊) = {α∊𝐿[subscript R](𝑉, 𝑊)|dim[subscript R] (𝑊/𝐹(α))<∞},
𝐴𝐼[subscript R](͟𝑉, 𝑊) = {α∊𝐿[subscript R](𝑉, 𝑊)|dim[subscript R] (𝑉/𝐹(α))<∞}
Moreover, let 𝐻, 𝑆 and 𝑇 be subsemigroups of 𝐺[subscript R](𝑉, 𝑊), 𝐴𝐼[subscript R](𝑉, ͟𝑊) and 𝐴𝐼[subscript R](͟𝑉, 𝑊), respectively. We show that 𝑂𝑀[subscript R](𝑉, 𝑊), 𝑂𝐸[subscript R](𝑉, 𝑊), 𝑂𝑀[subscript R](𝑉, 𝑊)∪𝐻, 𝑂𝐸[subscript R](𝑉, 𝑊)∪𝐻, 𝑂𝑀[subscript R](𝑉, 𝑊)∪𝑆, 𝑂𝐸[subscript R](𝑉, 𝑊)∪𝑆, 𝑂𝑀[subscript R](𝑉, 𝑊)∪𝑇 and 𝑂𝐸[subscript R](𝑉, 𝑊)∪𝑇 are semigroups. Furthermore, we determine whether they admit the structure of a semihyperring with zero.