#DinurEvraLivneLubotzkyMozes-3
"1 Introduction
A locally testable code (LTC) is an #ErrorCorrectingCode that has a property-tester. The tester reads 𝑞 bits (randomly - but not necessarily uniformly chosen) from a given word, and rejects words with probability proportional to
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>their distance from the code. The parameter 𝑞 is called the locality of the tester.
A random code has, with high probability, constant rate and distance, but locality that is proportional to the length. This is true even for random #LDPC codes [BHR05], and
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>a priori the mere existence of codes with constant locality is not obvious. The first LTCs appear implicitly in works on #ProgramChecking [BLR90] and on #ProbabilisticallyCheckableProofs (PCPs) [BFL91, LFKN92, BFLS91, AS98, ALM+98].
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>A formal definition of an LTC appeared simultaneously in several places [BFLS91, RS96, FS13, Aro94] (see [Gol10] for a detailed history.
[I could be mistaken, but it seems to me that arXiv:2111.04808v2 doesn't cite Goldreich correctly. Neither the title nor pages. In detail,
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>the reference in arXiv:2111.04808v2 is:
[Gol10] Oded Goldreich. Short Locally Testable Codes and Proofs: A Survey in Two Parts. Property Testing: Current Research and Surveys. LNCS 6650, pages 65–104. Springer, Berlin, Heidelberg, 2010.
In the published version of LNCS 6650,>
>i.e., in ISBN 978-3-642-22669-4, there IS an article by Goldreich titled "Short Locally Testable Codes and Proofs", but (1) the subtitle "A Survey in Two Parts" does NOT occur anywhere in ISBN 978-3-642-22669-4 (it does occur in a preprint version of Goldreich's survey though);>
> (2) in ISBN 978-3-642-22669-4, "Short Locally Testable Codes and Proofs" occurs on pages 333-372.
However, I now found the cause of the mismatch: Goldreich published this survey (with minor changes) twice, in similar books (see below). The ONLY #error in arXiv:2111.04808v2 is
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>that the wrong LNCS-number is given: the version of Goldreich's survey WITH a subtitle was published in LNCS 6390, not "6650". LG,I]
Spielman, in his PhD thesis [Spi96], discusses the possibility of having an #ErrorCorrecting code that is locally testable (he uses the term
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>‘checkable code’) and explains its potential applicability: [Spielman-quote]“A checker would be able to read only a constant number of bits of a received signal and then estimate the chance that a decoder will be able to correct the #errors, then the checker can instantly
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request a retransmission of that block,
before the decoder has wasted its time
trying to decode the message. Unfortunately
all known codes with local-checkers [sic] have
rate approaching zero."[end Spielman-quote]
Goldreich and Sudan [J. of the ACM, 53(4):558–655, 2006]
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"Local testability
By local testability we mean that the object can be tested for the natural property (i.e., being a codeword or a valid proof) using a small (typically constant)[Footnote: In this part, we associate local testability with tests
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>that perform a constant number of probes.] number of probes, each recovering individual bits in a standard representation of the object. Thus, local testability allows for super-fast testing of the corresponding objects. The tests are probabilistic and hence the result
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>is correct only with high probability.[Footnote: It is easy to see that deterministic tests will perform very poorly, and the same holds with respect to probabilistic tests that make no error.] Furthermore, correctness refers to a relaxed notion of deciding (which
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C. Teevs, ISBN 9783531164830: "[Er] ist ein Exot in der bundesdeutschen Politikerlandschaft..
Von..#Medien seit jeher gerne befragt.., ist er für die Parteiführung der #SPD zum..Ärgernis geworden.
..#Lauterbach [gehört] zu den unbeliebtesten Abgeordneten seiner Fraktion – aber
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>auch zu den spannendsten[!]
Wie kam es dazu, dass der C4-Professor für Gesundheitsökonomie sein eigenes Institut hinter sich ließ und sich um ein Bundestagsmandat bewarb?
Die biografischen und strukturellen Hintergründe dieses Seiteneinstiegs werden geschildert und analysiert."
[Versicherte], die immer noch auf Beitragssenkungen warten
[Notfallpatienten], die in der Ambulanz mehrfach zur Kasse gebeten wurden
[Gehbehinderte], denen die Kasse nicht mehr
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>Fahrt zum Arzt bezahlen wollte
[Diabetiker, MS-Kranke und Aids-Patienten], die nicht mehr als chronisch krank gelten sollten und sich vor hohen Zuzahlungen ängstigten
[Heimbewohner], die im Januar ihr gesamtes Taschengeld für Selbstbeteiligungen ausgeben sollten
[Arbeitnehmer]
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"Codes, proofs and their length
Codes are sets of strings (of equal length), typically, having a large pairwise distance. Equivalently, codes are viewed as mappings from short (𝑘-bit) strings to longer (𝑛-bit) strings, called codewords,
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>such that the codewords are distant from one another. We will focus on codes with relative constant distance; that is, every two 𝑛-bit codewords are at distance Ω(𝑛) apart. The length of the code is measured in terms of the length of the pre-image (i.e., we are interested
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>in the growth of 𝑛 as a function of 𝑘).
Turning to proofs, these are defined with respect to a verification procedure for assertions of a certain length, and their length is measured in terms of the length of the assertion. The verification procedure must satisfy the natural
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#GoldreichTestableCodesSurvey-2
"Abstract
We survey known results regarding locally testable codes and locally testable proofs (known as PCPs), with emphasis on the length of these constructs. Local testability refers to approximately testing large objects based on a very small
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>number of probes, each retrieving a single bit in the representation of the object.
This yields super-fast approximate #testing of the corresponding property (ie., be a codeword or a valid proof).
We also review the related concept of local decodable [recte 'locally decodable'
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>LG,I]
The survey consists of two independent (i.e., self-contained) parts that cover the same material at different levels of rigor and detail. Still, in spite of the repetitions, there may be a benefit in reading both parts.