Gluing n-tilting and n-cotilting Subcategories

The existence of maximal n-orthogonal subcategories

Article history: Received 30 April 2008 Available online 6 March 2009 Communicated by Luchezar L. Avramov

$n$-cocoherent rings‎, ‎$n$-cosemihereditary rings and $n$-V-rings

 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. ‎$R$...

MNDO Study of Nitrogen Atom Inversion in Piperazine, N,N'-Dimethylpiperazine and N,N'-Dichloropiperazine

MNDO semi-empirical SCF MO calculations are used to study the pyramidal nitrogen atom inversion and configurational equilibria in the title compounds.

Solvatochromic Properties of Heteroleptic Copper(II) Complexes Containing N,N,N',N'-Tetramethylethylenediamine and 2-Aacetylcyclopentanone Ligands

Three new heteroleptic copper(II) complexes, [(tmen)Cu(dike)H2O]X where tmen = N,N,N',N'-tetramethylethylenediamine, dike = 2-acetylcyclopentanone anion and X= ClO4- (1), Cl- (2) and Br- (3) are prepared and characterized by elemental analyses, molar conductance measurements and IR and UV-Vis spectroscopy techniques. The complex 1 is fairly soluble in various organic solvents and demonstrates d...

On $n$-ary Hypergroups and Fuzzy $n$-ary Homomorphism