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Sequential modelling entails making sense of sequential data, which naturally occurs in a wide array of domains. One example is systems that interact with users, log user actions and behaviour, and make recommendations of items of potential…

Information Retrieval · Computer Science 2021-09-15 Christian Hansen

The structure of covariant instruments is studied and a general structure theorem is derived. A detailed characterization is given to covariant instruments in the case of an irreducible representation of a locally compact group.

Mathematical Physics · Physics 2009-10-16 Claudio Carmeli , Teiko Heinosaari , Alessandro Toigo

In this paper we propose a new observability property for nonautonomous linear control systems in finite dimension; the nonuniform complete observability, which is more general than the uniform complete observability. The main result of…

Optimization and Control · Mathematics 2024-10-08 Ignacio Huerta

In empirical studies, the data usually don't include all the variables of interest in an economic model. This paper shows the identification of unobserved variables in observations at the population level. When the observables are distinct…

Econometrics · Economics 2022-12-07 Yingyao Hu

We formulate a general program for [...] analyzing continuous, differential weak, simultaneous measurements of noncommuting observables, which focuses on describing the measuring instrument autonomously, without states. The Kraus operators…

Quantum Physics · Physics 2023-08-30 Christopher S. Jackson , Carlton M. Caves

We give conditions for when two Euler products are the same given that they satisfy a functional equation and their coefficients are not too large and do not differ from each other by too much. Additionally, we prove a number of…

Number Theory · Mathematics 2025-05-13 David W. Farmer , Ameya Pitale , Nathan C. Ryan , Ralf Schmidt

Let $A$ and $B$ be two densely defined unbounded closeable operators in a Hilbert space such that their unbounded operator products $AB$ and $BA$ are also densely defined. Then all four operators possess adjoints and we obtain new inclusion…

Functional Analysis · Mathematics 2013-12-23 Karl Gustafson , Mohammed Hichem Mortad

We study the sequential product, the operation $p * q = \sqrt{p} q \sqrt{p}$ on the set of effects of a von Neumann algebra that represents sequential measurement of first $p$ and then $q$. We give four axioms which completely determine the…

Operator Algebras · Mathematics 2016-10-12 Abraham Westerbaan , Bas Westerbaan

The article reviews different definitions for a convolutional code which can be found in the literature. The algebraic differences between the definitions are worked out in detail. It is shown that bi-infinite support systems are dual to…

Optimization and Control · Mathematics 2007-07-16 Joachim Rosenthal

We develop the theory of categories of measurable fields of Hilbert spaces and bounded fields of bounded operators. We examine classes of functors and natural transformations with good measure theoretic properties, providing in the end a…

Category Theory · Mathematics 2007-05-23 D. N. Yetter

An observability problem for linear autonomous distributed systems in the class of linear operations is considered. A criterion of observability with respect to terminal state has been proved. A connection with observability with respect to…

solv-int · Physics 2008-02-03 B. Shklyar

A general scheme to seek for the relations between entanglement and bservables is proposed in principle. In two-qubit systems with enough general Hamiltonian, we find the entanglement to be the functions of observables for six kinds of…

Quantum Physics · Physics 2007-05-23 An Min Wang

We start from the observation that, anytime two Markov generators share an eigenvalue, the function constructed from the product of the two eigenfunctions associated to this common eigenvalue is a duality function. We push further this…

Probability · Mathematics 2023-09-08 Frank Redig , Federico Sau

Usually, mathematical objects have highly parallel interpretations. In this paper, we consider them as sequential constructors of other objects. In particular, we prove that every reflexive directed graph can be interpreted as a program…

Combinatorics · Mathematics 2007-10-27 Serge Burckel

This study introduces a data-driven, machine learning-based method to detect suitable control variables and instruments for assessing the causal effect of a treatment on an outcome in observational data. Our approach tests the joint…

Econometrics · Economics 2026-05-20 Nicolas Apfel , Julia Hatamyar , Martin Huber , Jannis Kueck

We study sequential measurement scenarios where the system is repeatedly subjected to the same measurement process. We first provide examples of such repeated measurements where further repetitions of the measurement do not increase our…

Quantum Physics · Physics 2016-09-14 Erkka Haapasalo , Teiko Heinosaari , Yui Kuramochi

Instrumental variables are a popular study design for the estimation of treatment effects in the presence of unobserved confounders. In the canonical instrumental variables design, the instrument is a binary variable. In many settings,…

Methodology · Statistics 2024-10-10 Prabrisha Rakshit , Alexander Levis , Luke Keele

We study here a sequence of secondary measures, so called because the set of secondary polynomials on a given term become orthogonal for the next measure. The main result is a formula making explicit the density of any term of the sequence,…

Classical Analysis and ODEs · Mathematics 2011-04-26 Roland Groux

Consider a sequence of real-valued functions of a real variable given by a homogeneous linear recursion with differentiable coefficients. We show that if the functions in the sequence are differentiable, then the sequence of derivatives…

Functional Analysis · Mathematics 2025-03-05 Dávid Papp , Kolos Csaba Ágoston

We propose alternative definitions of classical states and quantumness witnesses by focusing on the algebra of observables of the system. A central role will be assumed by the anticommutator of the observables, namely the Jordan product.…

Mathematical Physics · Physics 2013-12-24 Paolo Facchi , Leonardo Ferro , Giuseppe Marmo , Saverio Pascazio