131 research outputs found
The kind of silence: managing a reputation for voluntary disclosure in financial markets
No full textWe create a continuous-time setting in which to investigate how the management of a firm controls a dynamic choice between two generic voluntary disclosure decision rules (strategies) in the period between two consecutive mandatory disclosure dates: one with full and transparent disclosure termed candid, the other, termed sparing, under which values only above a dynamic threshold are disclosed. We show how parameters of the model such as news intensity, pay-for-performance and time-to-mandatory-disclosure determine the optimal choice of candid versus sparing strategies and the optimal times for management to switch between the two. The model presented develops a number of insights, based on a very simple ordinary differential equation characterizing equilibrium in a piecewise-deterministic model, derivable from the background Black-Scholes model and Poisson arrival of signals of firm value. It is shown that in equilibrium when news intensity is low a firm may employ a candid disclosure strategy throughout, but will otherwise switch (alternate) between periods of being candid and periods of being sparing with the truth (or the other way about). Significantly, with constant pay-for-performance parameters, at most one switching can occur
The sound of silence: equilibrium filtering and optimal censoring in financial markets
No full textFollowing the approach of standard filtering theory, we analyse investor valuation of firms, when these are modelled as geometric-Brownian state processes that are privately and partially observed, at random (Poisson) times, by agents. Tasked with disclosing forecast values, agents are able purposefully to withhold their observations; explicit filtering formulae are derived for downgrading the valuations in the absence of disclosures. The analysis is conducted for both a solitary firm and m co-dependent firms
Urządzenie wibracyjne do suchej regeneracji masy formierskiej opis patentowy nr 157972 /
No full textTyt. z ekranu tyt.Data zgłoszenia 29 grudnia 1988.Nr zgłoszenia 276901.Zgłoszenie ogłoszono 9 lipca 1990 BUP 14/90.O udzieleniu patentu ogłoszono 31 lipca 1992 WUP 07/92.Pozostali twórcy wynalazku: Leszek Bodzoń, Józef Dańko, Adam Sroczyński, Kazimierz Słota, Ryszard Ostaszewski, Mieczysław Kowalski, Wojciech Kierat.Dostępny także w wersji drukowanej.Tryb dostępu: Internet
Topological regular variation: I. Slow variation
No full textAbstractMotivated by the Category Embedding Theorem, as applied to convergent automorphisms (Bingham and Ostaszewski (in press) [11]), we unify and extend the multivariate regular variation literature by a reformulation in the language of topological dynamics. Here the natural setting are metric groups, seen as normed groups (mimicking normed vector spaces). We briefly study their properties as a preliminary to establishing that the Uniform Convergence Theorem (UCT) for Baire, group-valued slowly-varying functions has two natural metric generalizations linked by the natural duality between a homogenous space and its group of homeomorphisms. Each is derivable from the other by duality. One of these explicitly extends the (topological) group version of UCT due to Bajšanski and Karamata (1969) [4] from groups to flows on a group. A multiplicative representation of the flow derived in Ostaszewski (2010) [45] demonstrates equivalence of the flow with the earlier group formulation. In companion papers we extend the theory to regularly varying functions: we establish the calculus of regular variation in Bingham and Ostaszewski (2010) [13] and we extend to locally compact, σ-compact groups the fundamental theorems on characterization and representation (Bingham and Ostaszewski (2010) [14]). In Bingham and Ostaszewski (2009) [15], working with topological flows on homogeneous spaces, we identify an index of regular variation, which in a normed-vector space context may be specified using the Riesz representation theorem, and in a locally compact group setting may be connected with Haar measure
Homomorphisms from functional equations: The Goldie equation, II
No full textThis first of three sequels to Homomorphisms from Functional equations: The Goldie equation (Ostaszewski in Aequationes Math 90:427–448, 2016) by the second author—the second of the resulting quartet—starts from the Goldie functional equation arising in the general regular variation of our joint paper (Bingham et al. in J Math Anal Appl 483:123610, 2020). We extend the work there in two directions. First, we algebraicize the theory, by systematic use of certain groups—the Popa groups arising in earlier work by Popa, and their relatives the Javor groups. Secondly, we extend from the original context on the real line to multi-dimensional (or infinite-dimensional) settings
Topological regular variation: III. Regular variation
No full textAbstractThis paper extends the topological theory of regular variation of the slowly varying case of Bingham and Ostaszewski (2010) [5] to the regularly varying functions between metric groups, viewed as normed groups (see also Bingham and Ostaszewski (2010) [6]). This employs the language of topological dynamics, especially flows and cocycles. In particular we show that regularly varying functions obey the chain rule and in the non-commutative context we characterize pairs of regularly varying functions whose product is regularly varying. The latter requires the use of a ‘differential modulus’ akin to the modulus of Haar integration
The Goldie equation: III. Homomorphisms from functional equations
No full textThis is the second of three sequels to (Ostaszewski in Aequat Math 90:427–448, 2016)—the third of the resulting quartet—concerning the real-valued continuous solutions of the multivariate Goldie functional equation (GFE) below of Levi–Civita type. Following on from the preceding paper (Bingham and Ostaszewski in Homomorphisms from Functional Equations: II. The Goldie Equation, arXiv:1910.05816), in which these solutions are described explicitly, here we characterize (GFE) as expressing homomorphy (in all but some exceptional “improper” cases) between multivariate Popa groups, defined and characterized earlier in the sequence. The group operation involves a form of affine addition (with local scalar acceleration) similar to the circle operation of ring theory. We show the affine action in (GFE)may be replaced by a general continuous acceleration yielding a functional equation (GGE) which it emerges has the same solution structure as (GFE). The final member of the sequence (Bingham and Ostaszewski, The Gołąb–Schinzel and Goldie functional equations in Banach algebras, arXiv:2105.07794) considers the richer framework of a Banach algebra which allows vectorial acceleration, giving the closest possible similarity to the circle operation
Unreliable narrator in feature film
No full textAutor przedstawia funkcje narratora niewiarygodnego w filmach fabularnych, w kontekście definicji, jaką dla tej instancji narracyjnej zaproponował w literaturoznawstwie Wayne C. Booth (w książce The Rhetoric of Fiction /1961/). Za cechę konstytutywną konstrukcji narratora niewiarygodnego w dziele literackim Booth uznał dystans, jaki stopniowo powstaje między autorem wpisanym w tekst a narratorem. Stopniowa utrata zaufania do postaci snującej opowieść zachęca czytelnika do wspólnej z autorem oceny jego postawy. Jednak gdy narrator okazuje się już niegodny zaufania, zmienia się cały efekt dzieła. Ostaszewski przywołuje różnorodne przykłady filmów, śledząc rodzaje przejawiania się takiej właśnie instancji narracyjnej. Za kluczowe dla wyjaśnienia form niewiarygodności we współczesnych filmach autor uznaje kategorię ironii, i to zarówno na płaszczyźnie komunikacyjnej, jak i estetycznej. W podsumowaniu Ostaszewski stwierdza, że uznanie, iż mamy do czynienia z narratorem niewiarygodnym, jest strategią interpretacyjną, którą można się posłużyć w trakcie lektury dzieła filmowego w celu zintegrowania przedstawionych w filmie zdarzeń w spójną i logiczną historię.The author presents the function of an unreliable narrator in feature films, in the context of the definition proposed by Wayne C. Booth (in The Rhetoric of Fiction, 1961). Booth considers the constitutive characteristic of the unreliable narrator in literature to be the distance that gradually opens between the author and the narrator. The gradual loss of trust towards the storyteller invites the reader to evaluate his attitude. When the narrator turns out to be completely untrustworthy, the entire effect of the text is transformed. Ostaszewski lists a number of films that feature unreliable narrators, and shows different versions of this type of narration. Irony turns out to be the key element in understanding untrustworthiness in contemporary film. Identifying the unreliable narrator is a means through which one can integrate events present in the film into a coherent and logical construction
Subdominant eigenvalue location and the robustness of dividend policy irrelevance
No full textThis paper, on subdominant eigenvalue location of a bordered diagonal matrix, is the mathematical sequel to an accounting paper by Gao, Ohlson, Ostaszewski [7]. We explore the following characterization of dividend-policy irrelevance (DPI) to equity valuation in a multi-dimensional linear dynamics framework L: DPI occurs under L when discounting the expected dividend stream by a constant interest rate iff that rate is equal to the dominant eigenvalue of the canonical principal submatrix A of L.This is justifiably the ‘latent’ (or gross) rate of return, since the principal submatrix relates the state variables to each other but with dividend retention. We findthat DPI reduces to the placement of the maximum eigenvalue of L between the dominant and subdominant eigenvalues of A.We identify a special role, and a lower bound, for the coefficient measuring the year-on-year dividend-on-dividend sensitivity in achieving robust equity valuation (independence of small variations in the dividend policy)
The Unreliable Narrator in Feature Film
No full textAutor przedstawia funkcje narratora niewiarygodnego w filmach fabularnych, w kontekście definicji, jaką dla tej instancji narracyjnej zaproponował w literaturoznawstwie Wayne C. Booth (w książce The Rhetoric of Fiction /1961/). Za cechę konstytutywną konstrukcji narratora niewiarygodnego w dziele literackim Booth uznał dystans, jaki stopniowo powstaje między autorem wpisanym w tekst a narratorem. Stopniowa utrata zaufania do postaci snującej opowieść zachęca czytelnika do wspólnej z autorem oceny jego postawy. Jednak gdy narrator okazuje się już niegodny zaufania, zmienia się cały efekt dzieła. Ostaszewski przywołuje różnorodne przykłady filmów, śledząc rodzaje przejawiania się takiej właśnie instancji narracyjnej. Za kluczowe dla wyjaśnienia form niewiarygodności we współczesnych filmach autor uznaje kategorię ironii, i to zarówno na płaszczyźnie komunikacyjnej, jak i estetycznej. W podsumowaniu Ostaszewski stwierdza, że uznanie, iż mamy do czynienia z narratorem niewiarygodnym, jest strategią interpretacyjną, którą można się posłużyć w trakcie lektury dzieła filmowego w celu zintegrowania przedstawionych w filmie zdarzeń w spójną i logiczną historię.The author presents the function of an unreliable narrator in feature films, in the context of the definition proposed by Wayne C. Booth (in The Rhetoric of Fiction, 1961). Booth considers the constitutive characteristic of the unreliable narrator in literature to be the distance that gradually opens between the author and the narrator. The gradual loss of trust towards the storyteller invites the reader to evaluate his attitude. When the narrator turns out to be completely untrustworthy, the entire effect of the text is transformed. Ostaszewski lists a number of films that feature unreliable narrators, and shows different versions of this type of narration. Irony turns out to be the key element in understanding untrustworthiness in contemporary film. Identifying the unreliable narrator is a means through which one can integrate events present in the film into a coherent and logical construction
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