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Frederik Herzberg

Publications and source records attributed to Frederik Herzberg.

5 recordsLinked to original sources
arXiv2018

Hyperfinite Construction of $G$-expectation

The hyperfinite $G$-expectation is a nonstandard discrete analogue of $G$-expectation (in the sense of Robinsonian nonstandard analysis). A lifting of a continuous-time $G$-expectation operator is defined as a hyperfinite $G$-expectation which is infinitely close, in the sense of nonstandard topology, to the continuous-time $G$-expectation. We develop the basic theory for hyperfinite $G$-expectations and prove an existence theorem for liftings of (continuous-time) $G$-expectation. For the proof of the lifting theorem, we use a new discretization theorem for the $G$-expectation (also established in this paper, based on the work of Dolinsky et al. [Weak approximation of $G$-expectations, Stoch. Proc. Appl. 122(2), (2012), pp.664--675]).

q-fin.MF↗
arXiv2014

Fermat, Leibniz, Euler, and the gang: The true history of the concepts of limit and shadow

Fermat, Leibniz, Euler, and Cauchy all used one or another form of approximate equality, or the idea of discarding "negligible" terms, so as to obtain a correct analytic answer. Their inferential moves find suitable proxies in the context of modern theories of infinitesimals, and specifically the concept of shadow. We give an application to decreasing rearrangements of real functions.

math.HO↗
arXiv2005

On measures of unfairness and an optimal currency transaction tax

The purpose of the present paper is the analysis of a model describing how herd behaviour and self-fulfilling prophecies can influence currency exchange rates, and what the impact of a currency transaction tax would be. These considerations yield a stochastic differential equation that can be studied using the methods of infinitesimal analysis. We will show, using a suitable notion of unfairness for discounted price processes which measures the distance from being a martingale, that the fairest tax rate is the maximal one subject to the condition that it does not affect real-economic speculation.

math.PR↗
arXiv2004

The fairest price of an asset in an environment of temporary arbitrage

In practice there are temporary arbitrage opportunities arising from the fact that prices for a given asset at different stock exchanges are not instantaneously the same. We will show that even in such an environment there exists a ``fairest measure'' (instead of a martingale measure), albeit not necessarily unique. For this end, we define and analyse quantitative notions of unfairness in complete as well as incomplete market settings.

math.PR↗