A subgroup H is said to be weakly c∗-normal in a group G if there exists a subnormal subgroup K of G such that HK = G and H ∩ K is s-quasinormally embedded in G. We give some results which generalize some authors’ results.

Consider the question: which finite groups operate as symmetries of the complex projective plane P’(C)? Any finite subgroup of &X,(C) acts as a group of collineations and these give the linear models. The list of such groups is relatively short [MBD] but contains, for example, a groups of rank < 2, subgroups of U(Z), and the simple groups A,, A,, an PSL(F,). It turns out that these linear group...

In this paper we consider the continuous piecewise linear finite element approximation of the following problem: Given p € (1, oo), /, and g , find u such that -V • (\Vu\"-2Vu) = f iniîcR2, u = g on a«. The finite element approximation is defined over Í2* , a union of regular triangles, yielding a polygonal approximation to Q. For sufficiently regular solutions u , achievable for a subclass of ...

Generalizing [ShSp], for every n < ω we construct a ZFC-model where the distributivity number of r.o.(P(ω)/fin), h(n + 1), is smaller than the one of r.o.(P(ω)/fin). This answers an old problem of Balcar, Pelant and Simon (see [BaPeSi]). We also show that both of Laver and Miller forcing collapse the continuum to h(n) for every n < ω, hence by the first result, consistently they collapse it bel...