Let T : I ?! I be a Lasota-Yorke map on the interval I, let Y be a non trivial sub-interval of I and g 0 : I ?! R + , be a strictly positive potential which belongs to BV and admits a conformal measure m. We give constructive conditions on Y ensuring the existence of absolutely continuous (w.r.t. m) conditionally invariant probability measures to non absorption in Y. These conditions imply also...

We prove stability of the isolated eigenvalues of transfer operators satisfying a Lasota-Yorke type inequality under a broad class of random and nonrandom perturbations including Ulam-type discretizations. The results are formulated in an abstract framework.

Thomas Birch (1705-66), Secretary of the Royal Society from 1752 to 1765, and Philip Yorke, second Earl of Hardwicke (1720-90), wrote a 'Weekly Letter' from 1741 to 1766, an unpublished correspondence of 680 letters now housed in the British Library (Additional Mss 35396-400). The article examines the dimensions and purposes of this correspondence, an important conduit of information for the in...

As well-known, the concept "hypercyclic" in operator theory is the same as the concept "transitive" in dynamical system. Now the class of hypercyclic operators is well studied. Following the idea of research in hypercyclic operators, we consider classes of operators with some kinds of chaotic properties in this article. First of all, the closures of the sets of all Li-Yorke chaotic operators or...

Introduction.?About eighteen months ago, we (Napier and Sen, 1940) published a preliminary paper on the treatment of kala-azar by 4 : 4'-diamidino stilbene. At the time our paper was sent to press, there were in the literature? that had arrived in this country?only two detailed reports on cases treated by this drug (Adams and Yorke, 1939; and Adler and Rachmilewitz, 1939). Since then a small sp...