ornamental geophytes (ornamental flower bulbs) are international and national heritage considering their contribution to people's life quality around the world. iranian habitats support about 8000 species of flowering plants (belonging to 167 families and 100 genera) of which almost 1700 are endemic. iran is a rich country in terms of distribution of bulbous plants. more than 200 species of bul...

in this study, some habitat characteristics of iranian rose (hulthemia persica) were studied in gonbad watershed in hamedan providence, iran. soil samples were taken by a systematic randomized method at elevation 2000-2400 m above sea level. samples were taken from 0-30 cm depth. in the laboratory, n, p, k% and organic matter (oc%), soil acidity (ph), conductivity (ec) and soil texture were det...

We state several conditions under which comultiplication and weak comultiplication modulesare cyclic and study strong comultiplication modules and comultiplication rings. In particular,we will show that every faithful weak comultiplication module having a maximal submoduleover a reduced ring with a finite indecomposable decomposition is cyclic. Also we show that if M is an strong comultiplicati...

Let $Gamma$ be a group, $Gamma'$ a subgroup of $Gamma$ with finite index and $M$ be a $Gamma$-module. We show that $M$ is cotorsion if and only if it is cotorsion as a $Gamma'$-module. Using this result, we prove that the global cotorsion dimensions of rings $ZGamma$ and $ZGamma'$ are equal.

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, ...