In this paper, we consider the problem of formal iteration. We construct an area preserving mapping which does not have any square root. This leads to a counterexample Moser’s existence theorem for interpolation problem. give examples transformation groups such that iteration has solution every element

We try to control many cardinal characteristics by working with a notion of orthogonality between two families of forcings. We show that b < g is consistent. This work is dedicated to James Baumgartner on the occasion of his 60th birthday.

Although ytterbium was named by the Swiss chemist Jean de Marignac in 1878, his ‘element’ was subsequently split into two in 1905: ytterbium and lutetium. The atomic weight of the ‘new’ ytterbium was later published in 1907 — so when was ytterbium actually discovered? The story begins on 13 June 1726, more than 150 years before it first received its name. On that date an agreement was signed al...

The aim of this paper is to present some modifications of the biomorphs generation algorithm introduced by Pickover in 1986. A biomorph stands for biological morphologies. It is obtained by a modified Julia set generation algorithm. The biomorph algorithm can be used in the creation of diverse and complicated forms resembling invertebrate organisms. In this paper the modifications of the biomor...