let r be a commutative noetherian ring. we study the behavior of injectiveand at dimension of r-modules under the functors homr(-,-) and -×r-.

let r be an associative ring with identity, c(r) be the category of com-plexes of r-modules and flat(c(r)) be the class of all at complexes of r-modules. we show that the at cotorsion theory (flat(c(r)); flat(c(r))−)have enough injectives in c(r). as an application, we prove that for each atcomplex f and each complex y of r-modules, exti (f,x)= 0, whenever ris n-perfect and i > n.

background: malocclusion, as a worldwide issue, can cause a lot of problems for patients. panoramic (pr) and lateral cephalometric (lcr) radiographs are both usually indicated for orthodontic treatments. the aim of this study was to analyze vertical and sagittal parameters of both jaws on prs and to compare them on lcrs. materials and methods: in this cross sectional study, 61 samples from all ...

let r be a right gf-closed ring with finite left and right gorenstein global dimension. we prove that if i is an ideal of r such that r/i is a semi-simple ring, then the gorensntein flat dimensnion of r/i as a right r-module and the gorensntein injective dimensnnion of r/i as a left r-module are identical. in particular, we show that for a simple module s over a commutative gorensntein ring r, ...

this study focused on the effect of teaching collocations on the awareness of two affective dimensions, evaluation and potency dimensions, of deep vocabulary knowledge as well as the general vocabulary knowledge of efl students. sixty intermediate efl female adult learners participated in this study; they were chosen among 90 students through the pet and a general vocabulary knowledge test. the...

Let $G$ be a simple connected graph. In this paper, Szeged dimension and PI$_v$ dimension of graph $G$ are introduced. It is proved that if $G$ is a graph of Szeged dimension $1$ then line graph of $G$ is 2-connected. The dimensions of five composite graphs: sum, corona, composition, disjunction and symmetric difference with strongly regular components is computed. Also explicit formulas of Sze...