101,205 research outputs found
On the Impossibility of Probabilistic Proofs in Relativized Worlds
We initiate the systematic study of probabilistic proofs in relativized worlds, where the goal is to understand, for a given oracle, the possibility of "non-trivial" proof systems for deterministic or nondeterministic computations that make queries to the oracle.
This question is intimately related to a recent line of work that seeks to improve the efficiency of probabilistic proofs for computations that use functionalities such as cryptographic hash functions and digital signatures, by instantiating them via constructions that are "friendly" to known constructions of probabilistic proofs. Informally, negative results about probabilistic proofs in relativized worlds provide evidence that this line of work is inherent and, conversely, positive results provide a way to bypass it.
We prove several impossibility results for probabilistic proofs relative to natural oracles. Our results provide strong evidence that tailoring certain natural functionalities to known probabilistic proofs is inherent
Computer-Assisted Proofs and Symbolic Computations
We discuss some main points of computer-assisted proofs based
on reliable numerical computations. Such so-called self-validating numerical
methods in combination with exact symbolic manipulations result in very
powerful mathematical software tools. These tools allow proving mathematical
statements (existence of a fixed point, of a solution of an ODE, of
a zero of a continuous function, of a global minimum within a given range,
etc.) using a digital computer. To validate the assertions of the underlying
theorems fast finite precision arithmetic is used. The results are absolutely
rigorous.
To demonstrate the power of reliable symbolic-numeric computations we
investigate in some details the verification of very long periodic orbits of
chaotic dynamical systems. The verification is done directly in Maple, e.g.
using the Maple Power Tool intpakX or, more efficiently, using the C++
class library C-XSC.* This work is partially supported by DFG: KR1612/7-1
Basic hypergeometry of supersymmetric dualities
We introduce several new identities combining basic hypergeometric sums and
integrals. Such identities appear in the context of superconformal index
computations for three-dimensional supersymmetric dual theories. We give both
analytic proofs and physical interpretations of the presented identities.Comment: 25 pages, v2: minor corrections and comment
Effect of Legendrian Surgery
The paper is a summary of the results of the authors concerning computations
of symplectic invariants of Weinstein manifolds and contains some examples and
applications. Proofs are sketched. The detailed proofs will appear in our
forthcoming paper. In the Appendix written by S. Ganatra and M. Maydanskiy it
is shown that the results of this paper imply P. Seidel's conjecture equating
symplectic homology with Hochschild homology of a certain Fukaya category.Comment: v.4 is significantly extended, especially Sections 6 and 8. Several
other sections, including Appendix are rewritte
Exact Real Arithmetic with Perturbation Analysis and Proof of Correctness
In this article, we consider a simple representation for real numbers and
propose top-down procedures to approximate various algebraic and transcendental
operations with arbitrary precision. Detailed algorithms and proofs are
provided to guarantee the correctness of the approximations. Moreover, we
develop and apply a perturbation analysis method to show that our approximation
procedures only recompute expressions when unavoidable.
In the last decade, various theories have been developed and implemented to
realize real computations with arbitrary precision. Proof of correctness for
existing approaches typically consider basic algebraic operations, whereas
detailed arguments about transcendental operations are not available. Another
important observation is that in each approach some expressions might require
iterative computations to guarantee the desired precision. However, no formal
reasoning is provided to prove that such iterative calculations are essential
in the approximation procedures. In our approximations of real functions, we
explicitly relate the precision of the inputs to the guaranteed precision of
the output, provide full proofs and a precise analysis of the necessity of
iterations
The uses of Connes and Kreimer's algebraic formulation of renormalization theory
We show how, modulo the distinction between the antipode and the "twisted" or
"renormalized" antipode, Connes and Kreimer's algebraic paradigm trivializes
the proofs of equivalence of the (corrected) Dyson-Salam,
Bogoliubov-Parasiuk-Hepp and Zimmermann procedures for renormalizing Feynman
amplitudes. We discuss the outlook for a parallel simplification of
computations in quantum field theory, stemming from the same algebraic
approach.Comment: 15 pages, Latex. Minor changes, typos fixed, 2 references adde
Quantitative Models and Implicit Complexity
We give new proofs of soundness (all representable functions on base types
lies in certain complexity classes) for Elementary Affine Logic, LFPL (a
language for polytime computation close to realistic functional programming
introduced by one of us), Light Affine Logic and Soft Affine Logic. The proofs
are based on a common semantical framework which is merely instantiated in four
different ways. The framework consists of an innovative modification of
realizability which allows us to use resource-bounded computations as realisers
as opposed to including all Turing computable functions as is usually the case
in realizability constructions. For example, all realisers in the model for
LFPL are polynomially bounded computations whence soundness holds by
construction of the model. The work then lies in being able to interpret all
the required constructs in the model. While being the first entirely semantical
proof of polytime soundness for light logi cs, our proof also provides a
notable simplification of the original already semantical proof of polytime
soundness for LFPL. A new result made possible by the semantic framework is the
addition of polymorphism and a modality to LFPL thus allowing for an internal
definition of inductive datatypes.Comment: 29 page
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