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Daniel V. Tausk

Publications and source records attributed to Daniel V. Tausk.

At least 19 recordsLinked to original sources
arXiv2026

On the misuse of time-dependent models in assessing mask usage and excess mortality

The effectiveness of face masks as a population level intervention against respiratory viral transmission remains contested. While a large observational literature published during the COVID-19 pandemic reported beneficial effects, randomized controlled trials have consistently shown limited or no impact. An ecological analysis of European countries reported that average mask usage during the years 2020 and 2021 is positively associated with excess mortality in that same period in 24 European countries (Tausk and Spira, 2025). Such association remains after several attempts at controlling for confounding variables. This finding was later challenged by other authors and attributed to reverse causality (Cerqueira-Silva et al., 2026). In this paper, we reassess those criticisms in detail. We show that their analysis is fundamentally flawed, as the time-dependent regression framework used to refute the original findings yields spurious results partly due to the use of cumulative excess mortality as an outcome variable, thereby incorporating pre-intervention deaths and producing statistically significant effects even at impossible negative time lags. Diagnostic analyses further demonstrate that key assumptions of the model are violated, invalidating any association or causal interpretation. Finally, we present an original longitudinal analysis of mask usage designed to directly test the reverse causality hypothesis. By constructing multiple indices that capture mask adoption during distinct phases of pandemic waves, including interwave periods characterized by low mortality, we show that the association between mask usage and excess mortality persists and is not driven by reactive increases in masking. These findings provide substantial evidence that reverse causality provides, at most, a minor contribution to the observed association.

stat.AP↗
arXiv2022

On the incorrect use of Carlisle's method for dichotomous variables

In 2017, J. B. Carlisle has proposed a method for fraud detection in randomized controlled trials based on a comparison of reported baseline data between treatment groups. While Carlisle has only used the method for continuous variables, some authors have recently employed a naive adaption of the method for dichotomous variables. We explain why such adaptation leads to p-values that are wrong by orders of magnitude and we make a simple concrete proposal for correction of the method.

stat.AP↗
arXiv2022

Extension of $c_0(I)$-valued operators on spaces of continuous functions on compact lines

We investigate the problem of existence of a bounded extension to $C(K)$ of a bounded $c_0(I)$-valued operator $T$ defined on the subalgebra of $C(K)$ induced by a continuous increasing surjection $ϕ:K\to L$, where $K$ and $L$ are compact lines. Generalizations of some of the results of [6] about extension of $c_0$-valued operators are obtained. For instance, we prove that when a bounded extension of $T$ exists then an extension can be obtained with norm at most twice the norm of $T$. Moreover, the class of compact lines $L$ for which the $c_0$-extension property is equivalent to the $c_0(I)$-extension property for any continuous increasing surjection $ϕ:K\to L$ is studied.

math.FA↗
arXiv2019

A brief introduction to the Foundations of Quantum Theory and an analysis of the Frauchiger-Renner paradox

This is a short text covering some topics on the Foundations of Quantum Theory and it includes some comments on the recent Nature article by D. Frauchiger and R. Renner. The so-called "paradox" is simply due to a misunderstanding on the appropriate way to apply the quantum mechanical rules. The text is meant to be accessible to non physicists and the math is kept to a minimum (just some Linear Algebra and extremely elementary Probability Theory).

quant-ph↗
arXiv2018

Local extension property for finite height spaces

We introduce a new technique for the study of the local extension property (LEP) for boolean algebras and we use it to show that the clopen algebra of every compact Hausdorff space $K$ of finite height has LEP. This implies, under appropriate additional assumptions on $K$ and Martin's Axiom, that every twisted sum of $c_0$ and $C(K)$ is trivial, generalizing a recent result by Marciszewski and Plebanek.

math.FA↗
arXiv2016

Small Valdivia compacta and trees

We present a characterization of Valdivia compact spaces of small weight in terms of path spaces of trees and we use it to obtain (under $\diamondsuit$) a counterexample to a conjecture related to an open problem concerning twisted sums of $C(K)$ spaces.

math.GN↗
arXiv2014

Reply to "Maximal violation of Bell inequalities by position measurements"

In a recent article, Kiukas and Werner claim to have shown that Bohmian Mechanics does not make the same empirical predictions as ordinary Quantum Mechanics. More precisely, they have shown that ordinary Quantum Mechanics predicts maximal violations of the CHSH-Bell inequality for a certain experiment in which only position measurements are performed on two noninteracting entangled free non-relativistic particles. Kiukas and Werner claim that Bohmian Mechanics doesn't predict a violation of the CHSH-Bell inequality for that experiment. We explain that such claim is wrong and that the argument supporting their claim neglects the fact that Bohmian Mechanics does not satisfy all the assumptions needed to prove the CHSH-Bell inequality. We also clear up another few misconceptions about Bohmian Mechanics appearing in their article.

quant-ph↗
arXiv2014

On the $c_0$-extension property for compact lines

We present a characterization of the continuous increasing surjections $ϕ:K\to L$ between compact lines $K$ and $L$ for which the corresponding subalgebra $ϕ^*C(L)$ has the $c_0$-extension property in $C(K)$. A natural question arising in connection with this characterization is shown to be independent of the axioms of ZFC.

math.FA↗
arXiv2013

Extension property and complementation of isometric copies of continuous functions spaces

In this article we prove that every isometric copy of C(L) in C(K) is complemented if L is compact Hausdorff of finite height and K is a compact Hausdorff space satisfying the extension property, i.e., every closed subset of K admits an extension operator. The space C(L) can be replaced by its subspace C(L|F) consisting of functions that vanish on a closed subset F of L. We also study the class of spaces having the extension property, establishing some closure results for this class and relating it to other classes of compact spaces.

math.FA↗
arXiv2013

A note on the continuous self-maps of the ladder system space

We give a partial characterization of the continuous self-maps of the ladder system space K_S. Our results show that K_S is highly nonrigid. We also discuss reasonable notions of "few operators" for spaces C(K) with scattered K and we show that C(K_S) does not have few operators for such notions.

math.FA↗
arXiv2013

On extensions of $c_0$-valued operators

We study pairs of Banach spaces $(X,Y)$, with $Y\subset X$, for which the thesis of Sobczyk's theorem holds, namely, such that every bounded $c_0$-valued operator defined in $Y$ extends to $X$. We are mainly concerned with the case when $X$ is a $C(K)$ space and $Y\equiv C(L)$ is a Banach subalgebra of $C(K)$. The main result of the article states that, if $K$ is a compact line and $L$ is countable, then every bounded $c_0$-valued operator defined in $C(L)$ extends to $C(K)$.

math.FA↗
arXiv2011

Can We Make a Bohmian Electron Reach the Speed of Light, at Least for One Instant?

In Bohmian mechanics, a version of quantum mechanics that ascribes world lines to electrons, we can meaningfully ask about an electron's instantaneous speed relative to a given inertial frame. Interestingly, according to the relativistic version of Bohmian mechanics using the Dirac equation, a massive particle's speed is less than or equal to the speed of light, but not necessarily less. That is, there are situations in which the particle actually reaches the speed of light---a very non-classical behavior. That leads us to the question of whether such situations can be arranged experimentally. We prove a theorem, Theorem 5, implying that for generic initial wave functions the probability that the particle ever reaches the speed of light, even if at only one point in time, is zero. We conclude that the answer to the question is no. Since a trajectory reaches the speed of light whenever the quantum probability current psi-bar gamma^mu psi is a lightlike 4-vector, our analysis concerns the current vector field of a generic wave function and may thus be of interest also independently of Bohmian mechanics. The fact that the current is never spacelike has been used to argue against the possibility of faster-than-light tunnelling through a barrier, a somewhat similar question. Theorem 5, as well as a more general version provided by Theorem 6, are also interesting in their own right. They concern a certain property of a function psi: R^4 --> C^4 that is crucial to the question of reaching the speed of light, namely being transverse to a certain submanifold of C^4 along a given compact subset of space-time. While it follows from the known transversality theorem of differential topology that this property is generic among smooth functions psi: R^4 --> C^4, Theorem 5 asserts that it is also generic among smooth solutions of the Dirac equation.

quant-ph↗
arXiv2009

What Does the Free Will Theorem Actually Prove?

Conway and Kochen have presented a "free will theorem" (Notices of the AMS 56, pgs. 226-232 (2009)) which they claim shows that "if indeed we humans have free will, then [so do] elementary particles." In a more precise fashion, they claim it shows that for certain quantum experiments in which the experimenters can choose between several options, no deterministic or stochastic model can account for the observed outcomes without violating a condition "MIN" motivated by relativistic symmetry. We point out that for stochastic models this conclusion is not correct, while for deterministic models it is not new.

quant-ph↗
arXiv2006

An existence theorem for G-structure preserving affine immersions

We prove an existence result for local and global G-structure preserving affine immersions between affine manifolds. Several examples are discussed in the context of Riemannian and semi-Riemannian geometry, including the case of isometric immersions into Lie groups endowed with a left-invariant metric, and the case of isometric immersions into products of space forms.

math.DG↗