A certificate is a mathematical object that establishes the validity of a logical formula and that is self-contained, self-explanatory, and can be checked independently and automatically. Certificates arise naturally in many areas of mathematics, and in many different forms. In particular, certificates are common in the context of program verification, where they are used for automatic checking...

Vertex and edge connectivity are special cases of mixed connectivity, in which all edges and a specified set of vertices play a similar role. Certificates of k-connectivity for a graph are obtained by removing a subset of its edges, while preserving its connectivity up to k. We unify the previous work on connectivity certificates and extend it to handle mixed connectivity and multigraphs. Our t...

Browsers can detect malicious websites that are provisioned with forged or fake TLS/SSL certificates. However, they are not so good at detecting malicious websites if they are provisioned with mistakenly issued certificates or certificates that have been issued by a compromised certificate authority. Google proposed certificate transparency which is an open framework to monitor and audit certif...

Farkas’ lemma is a fundamental result from linear programming providing linear certificates for infeasibility of systems of linear inequalities. In semidefinite programming, such linear certificates only exist for strongly infeasible linear matrix inequalities. We provide nonlinear algebraic certificates for all infeasible linear matrix inequalities in the spirit of real algebraic geometry: A l...

In JDK 1.2, the security architecture supports fine grained access control. In the default implementation, Java runtime modules (classes) are signed, and permissions are configured through a configuration file using the signer’s identity and the loading location (URL) of the module. In a large network, the number of applets and the frequency of changes to the security policy will eventually gro...

It is often argued that certifiers have an incentive to offer inflated certificates, although they deny it. In this paper, we study a model in which a certifier is paid by sellers, and may offer them inflated certificates, but incurs costs if doing so. We find that the certifier may face a commitment problem: The certifier offers inflated certificates if the costs of offering the first inflated...

AIMS Sickness certificates are to provide information on a disease and its consequences on the patient's functioning. This information has implications for the patient's rights to sickness benefits and return-to-work measures. The objective of this study was to investigate the description of functioning in sickness certificates according to WHO's International Classification of Functioning, Dis...

Death certificates may lack accuracy and misclassify the cause of death. The validity of proxy-reported cause of death is not well established. The authors examined death records on 336 participants in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study, a national cohort study of 30,239 community-dwelling US adults (2003-2010). Trained experts used study data, medical r...

STUDY OBJECTIVE The aim was to report on the extent to which death certificates which specify that death occurred in hospital can be matched and linked with routine hospital inpatient information systems. DESIGN The study involved linkage of hospital records which specified that death occurred in hospital to corresponding death certificates; and linkage of death certificates which specified t...