let $r$ be a ring‎, ‎and let $n‎, ‎d$ be non-negative integers‎. ‎a right $r$-module $m$ is called $(n‎, ‎d)$-projective if $ext^{d+1}_r(m‎, ‎a)=0$ for every $n$-copresented right $r$-module $a$‎. ‎$r$ is called right $n$-cocoherent if every $n$-copresented right $r$-module is $(n+1)$-coprese-nted‎, ‎it is called a right co-$(n,d)$-ring if every right $r$-module is $(n‎, ‎d)$-projective‎. ‎$r$ ...

the zero-divisor graph of a commutative ring r with respect to nilpotent elements is a simple undirected graph $gamma_n^*(r)$ with vertex set z_n(r)*, and two vertices x and y are adjacent if and only if xy is nilpotent and xy is nonzero, where z_n(r)={x in r: xy is nilpotent, for some y in r^*}. in this paper, we investigate the basic properties of $gamma_n^*(r)$. we discuss when it will be eu...

The soil sorptivity, S, and saturated hydraulic conductivity, Ks, can be estimated from the inverse analysis of a cumulative infiltration curve using quasi-exact implicit (QEI) formulation or its corresponding 4-Terms (4T) approximation. Although these models consider as homogeneous media, there is no information about how heterogeneous profiles affect inferred properties. This work analyzes in...

The stability of a rock slope is strongly influenced by the pattern groundwater flow through fracture system, which may lead to an increase in water pressure partly open joints and consequent decrease wall strength. comprehension challenging but vital aspect engineering geology since fractures’ spatial distribution, connectivity, aperture guide both movement quantity within volume. In literatur...

‎let $r$ be a ring with involution $*$‎. ‎an additive mapping $t:rto r$ is called a left(respectively right) centralizer if $t(xy)=t(x)y$ (respectively $t(xy)=xt(y)$) for all $x,yin r$‎. ‎the purpose of this paper is to examine the commutativity of prime rings with involution satisfying certain identities involving left centralizers.