This paper contains the formal development of a correct algorithm from an implicit definition of the task to be performed. Each step of the development can be accompanied by a proof of its correctness. As well as ensu...
The spider structure in the photoelectron momentum distributions(PMDs)of ionized electrons from the hydrogen atom is simulated by solving the time-dependent Schrodinger equation(TDSE).We find that the spider structure...
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The spider structure in the photoelectron momentum distributions(PMDs)of ionized electrons from the hydrogen atom is simulated by solving the time-dependent Schrodinger equation(TDSE).We find that the spider structure exhibits sensitive dependence on carrier envelope phase(CEP)of the few-cycle *** elucidate the striking CEP dependence of the spider structure,we select three physical parameters IL,IR,and IR/IL to quantitatively characterize the variations of the spider structure induced by altering the *** is the sum of the left half panel of the transverse cut curves(i.e.,the sum of all the negative momenta along the laser polarization direction),IR is the sum of the right half panel of the transverse cut curves(i.e.,the sum of all the positive momenta along the laser polarization direction),and IR/IL is the ratio between the two *** parameters are shown to have monotonic relation with the CEP value,which is exploited to extract the *** anticipate that our method will be useful for obtaining CEPs encoded in the spider structure of PMDs.
Per Martin-Löfs Constructive Set Theory is a mathematical language with computation rules. It is primarily designed to be a language for mathematical reasoning. The language has a very simple semantics and its ru...
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ISBN:
(纸本)0897910605
Per Martin-Löfs Constructive Set Theory is a mathematical language with computation rules. It is primarily designed to be a language for mathematical reasoning. The language has a very simple semantics and its rules have a simple structure. Since it is a language for constructive mathematics, it is possible to execute the proof (the construction of a proposition) as a program. The language can be seen as a programming language without assignments and other side effects. Compared to traditional functional languages it has a very rich type structure in that the type of an expression can completely specify the task of the expres-tion. A sorting algorithm, for instance, can be conventionally specified to have a type sort: List(A) List(A) which is type-correct if sort is any function taking a list as argument and producing a list as result. It is, however, also possible to specify that sort is a function taking a list as argument and producing a sorted permutation of its input as result, i.e. sort:(l/x £ List(A)) (vy tList(A)) (Perm(x,y) x Sorted(y)) The type (or the task) of the program can be read as the proposition (Vx 6 List(A)) (3y e List(A) (Perm(x,y) & Sorted(y)) which is read "for all lists x, there is a sorted permutation y of x". We can prove that this proposition is true, using the rules of the language to construct a program for the task. If the proposition were not true, it would be impossible to find a a program for it and we would have had an impossible task. The types of Constructive Set Theory can be seen as a specification language for the programs, but of course there is only one language, avoiding the complexity of mixing a programming language with a logical language. The similarity (or rather: identity) between a mathematical proof of a given proposition and a program for a given task suggests that programming should be similar to the mathematicians activity of finding proofs. We have illustrated this with an example of how a proof of the Euclidean
Leveraged by the success of applications aiming at the 'free' sharing of data in the Internet, the paradigm of peer-to-peer (P2P) computing has had substantial consideration devoted to it recently. This paper ...
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An important aspect of system support for mobile computing involves alleviating the issues related to programming the underlying distributed system. Our approach to dealing with these issues is by means of programming...
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The control of a robot consists in: • computing the space environment of the mechanical arm • ordering the robot movements • collecting informations on the status of the physical arm (feedback) in order to make comput...
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This paper considers the k -set agreement problem in a synchronous distributed system model with send-omission failures in which at most f processes can fail by send-omission. We show that, in a system of n +1 process...
This paper considers the k -set agreement problem in a synchronous distributed system model with send-omission failures in which at most f processes can fail by send-omission. We show that, in a system of n +1 processes ( n +1) f ), no algorithm can solve k -set agreement in
⌊
f k ⌋
rounds. Our lower bound proof uses topological techniques to characterize subsets of executions of our model. The characterization has a surprisingly regular structure which leads to a simple and succinct proof. We also show that the lower bound is tight by exhibiting a new algorithm that solves k -set agreement in
⌊
f k ⌋ + 1 rounds.
Providing type interoperability consists in ensuring that, even if written by different programmers, possibly in different languages and running on different platforms, types that are supposed to represent the same so...
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Providing type interoperability consists in ensuring that, even if written by different programmers, possibly in different languages and running on different platforms, types that are supposed to represent the same software module are indeed treated as one single type. This form of interoperability is crucial in modern distributed programming. We present a pragmatic approach to deal with type interoperability in a dynamic and distributed environment. Our approach is based on an optimistic transport protocol, specific serialization mechanisms and a set of implicit type conformance rules. We experiment the approach over the .NET platform which we indirectly evaluate.
In this paper, based on the homotopy continuation method and the interval Newton method, an efficient algorithm is introduced to isolate the real roots of semi-algebraic system. Tests on some random examples and a var...
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