436 research outputs found
Activities of Samuel Hoare in Russia 1916
No full textThe article examines the formation and activities of the British intelligence officer S. Hoare in Russia. His memories as a witness of the last days of the Russian Empire are very useful for researchers. Relations with representatives of the Russian liberal opposition allowed S. Hoare to gather important information about the Russian economy. The author concludes that Samuel Hoare significantly influenced Russia’s strengthening of the continental blockade
RISINGTIDEFALLINGSTAR
No full textFrom the author of Leviathan, or, The Whale, comes a composite portrait of the subtle, beautiful, inspired and demented ways in which we have come to terms with our watery planet.In the third of his watery books, the author goes in pursuit of human and animal stories of the sea. Of people enchanted or driven to despair by the water, accompanied by whales and birds and seals familiar spirits swimming and flying with the author on his meandering odyssey from suburbia into the unknown.Along the way, he encounters drowned poets and eccentric artists, modernist writers and era-defining performers, wild utopians and national heroes famous or infamous, they are all surprisingly, and sometimes fatally, linked to the sea.Out of the storm-clouds of the twenty-first century and our restive time, these stories reach back into the past and forward into the future. This is a shape-shifting world that has never been certain, caught between the natural and unnatural, where the state between human and animal is blurred. Time, space, gender and species become as fluid as the sea.Here humans challenge their landbound lives through art or words or performance or myth, through the animal and the elemental. And here they are forever drawn back to the water, forever lost and found on the infinite sea
The Characterization Problem for Hoare Logics
No full textResearch by this author and others has shown that there are natural programming control language control structures which are impossible to describe accurately by means of Hoare axioms
James Hall’s (1856) Rostroconchs from the Mississippian of Indiana and Illinois
No full textAuthor Institution: Dept of Geology, Bowling Green State University, Bowling Green, OHHall (1856) described without illustrations six species of the rostroconch Conocardium in his study of the fauna of the Salem Limestone in Indiana and the Warsaw Shale in Illinois. The species represent five genera, two of which are new, Leptoconocardium and Kyoconocardium. Other species represent the genera Hippocardia Brown, 1843; Oxyprora Hoare, Mapes, and Yancey, 2002; and Diedrorynchus Hoare and Peck, 2005
Mechanizing Hoare Style Proof Outlines for Imperative Programs in Agda
No full textFormal verification of imperative programs can be carried out on paper by annotating programs to obtain an outline of a proof in the style of Hoare. This process has been mechanized by the introduction of Separation Logic and computer assisted verification tools. However, the tools fail to achieve the readability and convenience of manual paper proof outlines. This is a pity, because getting ideas and proofs across is essential for scientific research. I introduce a mechanization for proof outlines of imperative programs to interactively write human readable outlines in the dependently typed programming language and proof assistant Agda. I achieve this by introducing practical syntax and proof automation to write concise proof outlines for a simple imperative programming language based on λ-calculus. The proposed solution results in proof outlines that combine the readability of paper proof outlines and the precision of mechanization.Implementation in Agda can be found at: https://github.com/Olavhaasie/hoare-proof-outlinesComputer Scienc
Constraint Identification Using Modified Hoare Logic on Hybrid Models of Gene Networks
No full textWe present a new hybrid Hoare logic dedicated for a class of linear hybrid automata well suited to model gene regulatory networks. These automata rely on Thomas' discrete framework in which qualitative parameters have been replaced by continuous parameters called celerities. The identification of these parameters remains one of the keypoints of the modelling process, and is difficult especially because the modelling framework is based on a continuous time. We introduce Hoare triples which handle biological traces and pre/post-conditions. Observed chronometrical biological traces play the role of an imperative program for classical Hoare logic and our hybrid Hoare logic, defined by inference rules, is proved to be sound. Furthermore, we present a weakest precondition calculus (a la Dijkstra) which leads to constraints on dynamical parameters. Finally, we illustrate our "constraints generator" with a simplified circadian clock model describing the rhythmicity of cells in mammals on a 24-hour period
Formal verification of quantum algorithms using quantum hoare logic
No full text© The Author(s) 2019. We formalize the theory of quantum Hoare logic (QHL) [TOPLAS 33(6),19], an extension of Hoare logic for reasoning about quantum programs. In particular, we formalize the syntax and semantics of quantum programs in Isabelle/HOL, write down the rules of quantum Hoare logic, and verify the soundness and completeness of the deduction system for partial correctness of quantum programs. As preliminary work, we formalize some necessary mathematical background in linear algebra, and define tensor products of vectors and matrices on quantum variables. As an application, we verify the correctness of Grover’s search algorithm. To our best knowledge, this is the first time a Hoare logic for quantum programs is formalized in an interactive theorem prover, and used to verify the correctness of a nontrivial quantum algorithm
Approximate Relational Hoare Logic for Continuous Random Samplings
No full textAbstractApproximate relational Hoare logic (apRHL) is a logic for formal verification of the differential privacy of databases written in the programming language pWHILE. Strictly speaking, however, this logic deals only with discrete random samplings. In this paper, we define the graded relational lifting of the subprobabilistic variant of Giry monad, which described differential privacy. We extend the logic apRHL with this graded lifting to deal with continuous random samplings. We give a generic method to give proof rules of apRHL for continuous random samplings
Differential Hoare Logics and Refinement Calculi for Hybrid Systems with Isabelle/HOL
No full textWe present simple new Hoare logics and refinement calculi for hybrid systems in the style of differential dynamic logic. (Refinement) Kleene algebra with tests is used for reasoning about the program structure and generating verification conditions at this level. Lenses capture hybrid program stores in a generic algebraic way. The approach has been formalised with the Isabelle/HOL proof assistant. A number of examples explains the workflow with the resulting verification components
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