Issuing of certificates of origin in some economic integration agreements signed by Latin American countries

In the context of an economic integration agreement (EIA), the issuing and verification of certificates of origin are carried out in accordance with procedures which ensure compliance with the rules of origin. Each EIA has its own system of rules of origin with their corresponding procedures. The purpose of the rules is to define clearly the geographical provenance of a good which may benefit from preferential tariffs in the importing country. The main purpose of the rules of origin is to avoid the diversion of trade, so that preferential tariff treatment is applied only to those products negotiated between the parties. The rules of origin of an EIA are more important than the actual process of tariff reduction, as that process is concluded at some point in time, whereas the rules of origin remain applicable indefinitely.

Verification of Certificates of Origin in Chile

Origin procedures concern both the issuance and verification of certificates of origin. Certification of origin consists of demonstrating that a product complies with standards of origin that qualify a good for access to the corresponding tariff preferences in a destination market, and that no triangulation has occurred in this process. Verification of origin means not only formally checking the validity of the certificate of origin, but also ensuring that the merchandise covered by the certificate genuinely qualifies as originating. All trade agreements carry rules on origin procedures, which continue to apply after the corresponding tariff reduction programmes have concluded.  This edition of the bulletin examines the case of Chile, because of the large number of trade agreements the country has signed.

Certificates for Incremental Type Checking

The central topic of this thesis is the study of algorithms for type checking, both from the programming language and from the proof-theoretic point of view. A type checking algorithm takes a program or a proof, represented as a syntactical object, and checks its validity with respect to a specification or a statement. It is a central piece of compilers and proof assistants. We postulate that since type checkers are at the interface between proof theory and program theory, their study can let these two fields mutually enrich each other. We argue by two main instances: first, starting from the problem of proof reuse, we develop an incremental type checker; secondly, starting from a type checking program, we evidence a novel correspondence between natural deduction and the sequent calculus.

Reduced certificates for abstraction-carrying code

Abstraction-Carrying Code (ACC) has recently been proposed as a framework for mobile code safety in which the code supplier provides a program together with an abstraction whose validity entails compliance with a predefined safety policy. The abstraction plays thus the role of safety certifícate and its generation is carried out automatically by a fixed-point analyzer. The advantage of providing a (fixedpoint) abstraction to the code consumer is that its validity is checked in a single pass of an abstract interpretation-based checker. A main challenge is to reduce the size of certificates as much as possible while at the same time not increasing checking time. We introduce the notion of reduced certifícate which characterizes the subset of the abstraction which a checker needs in order to validate (and re-construct) the full certifícate in a single pass. Based on this notion, we instrument a generic analysis algorithm with the necessary extensions in order to identify the information relevant to the checker. We also provide a correct checking algorithm together with sufficient conditions for ensuring its completeness. The experimental results within the CiaoPP system show that our proposal is able to greatly reduce the size of certificates in practice.

Generation of reduced certificates in abstraction-carrying code

Abstraction-Carrying Code (ACC) has recently been proposed as a framework for mobile code safety in which the code supplier provides a program together with an abstraction whose validity entails compliance with a predefined safety policy. The abstraction plays thus the role of safety certifícate and its generation is carried out automatically by a fixed-point analyzer. The advantage of providing a (fixedpoint) abstraction to the code consumer is that its validity is checked in a single pass of an abstract interpretation-based checker. A main challenge is to reduce the size of certificates as much as possible while at the same time not increasing checking time. In this paper, we first introduce the notion of reduced certifícate which characterizes the subset of the abstraction which a checker needs in order to validate (and re-construct) the full certifícate in a single pass. Based on this notion, we then instrument a generic analysis algorithm with the necessary extensions in order to identify the information relevant to the checker.

Reduced certificates for abstraction-carrying code

Abstraction-Carrying Code (ACC) has recently been proposed as a framework for mobile code safety in which the code supplier provides a program together with an abstraction (or abstract model of the program) whose validity entails compliance with a predefined safety policy. The abstraction plays thus the role of safety certifícate and its generation is carried out automatically by a fixed-point analyzer. The advantage of providing a (fixed-point) abstraction to the code consumer is that its validity is checked in a single pass (i.e., one iteration) of an abstract interpretation-based checker. A main challenge to make ACC useful in practice is to reduce the size of certificates as much as possible while at the same time not increasing checking time. The intuitive idea is to only include in the certifícate information that the checker is unable to reproduce without iterating. We introduce the notion of reduced certifícate which characterizes the subset of the abstraction which a checker needs in order to validate (and re-construct) the full certifícate in a single pass. Based on this notion, we instrument a generic analysis algorithm with the necessary extensions in order to identify information which can be reconstructed by the single-pass checker. Finally, we study what the effects of reduced certificates are on the correctness and completeness of the checking process. We provide a correct checking algorithm together with sufficient conditions for ensuring its completeness. Our ideas are illustrated through a running example, implemented in the context of constraint logic programs, which shows that our approach improves state-of-the-art techniques for reducing the size of certificates.

Ship certificates, 1791

This folder contains two handwritten certificates authorizing Croswell's voyage from Boston to London.

[Receipt for certificates of funded debt], 1791 January 28

Printed Commissioner's Office receipt form acknowledging three certificates of funded debt received by Caleb Gannett from Nathaniel Appleton, Commissioner of Loans in the State of Massachusetts. The receipt, No. 712, is signed by Gannett and dated January 28, 1791.