Extending Nunchaku to Dependent Type Theory

Nunchaku is a new higher-order counterexample generator based on a sequence of transformations from polymorphic higher-order logic to first-order logic. Unlike its predecessor Nitpick for Isabelle, it is designed as a stand-alone tool, with frontends for various proof assistants. In this short paper, we present some ideas to extend Nunchaku with partial support for dependent types and type classes, to make frontends for Coq and other systems based on dependent type theory more useful.Comment: In Proceedings HaTT 2016, arXiv:1606.0542

Language and Proofs for Higher-Order SMT (Work in Progress)

Satisfiability modulo theories (SMT) solvers have throughout the years been able to cope with increasingly expressive formulas, from ground logics to full first-order logic modulo theories. Nevertheless, higher-order logic within SMT is still little explored. One main goal of the Matryoshka project, which started in March 2017, is to extend the reasoning capabilities of SMT solvers and other automatic provers beyond first-order logic. In this preliminary report, we report on an extension of the SMT-LIB language, the standard input format of SMT solvers, to handle higher-order constructs. We also discuss how to augment the proof format of the SMT solver veriT to accommodate these new constructs and the solving techniques they require.Comment: In Proceedings PxTP 2017, arXiv:1712.0089

Closing the communications loop on the computerized peer‐assessment of essays

The use of self‐ and peer‐assessment is not new to higher education. Traditionally its use has required the complex and time‐consuming management of coursework submissions by the tutor, in an attempt to maintain validity and anonymity of the assessment process. In the last few years a number of computerized systems have been developed that are capable of automatically supporting, managing and performing the assessment process. The requirement for student anonymity and the release of the tutor from the process of marking have reduced the ability to develop the iterative process of feedback. This feedback is considered essential in supporting student learning and developing reflective practice. This paper describes the enhancement of a computerized assessment system to support anonymous computer‐mediated discussion between marker and marked having previously performed peer‐assessment. A detailed description is provided of the integrated assessment process, and an analysis of the use of this anonymous discussion is presented. Anonymous student feedback is presented and analyzed with respect to the perceived benefits of using the system with respect to enhancing the student learning process

Validating a method to enable distributed development teams in an engineering simulator

To improve distributed collaboration of product development teams, the EDiT method (Enabling Distributed Teams) was developed as support. To successfully introduce the EDiT method into development practice, it is essential to validate the method in a practice-oriented but at the same time controllable environment. Therefore, this contribution aims to validate the EDiT method in the laboratory-based validation environment of an engineering simulator. The engineering simulator covers the further development of a bending machine within two agile sprints in two days. Through the validation in a test and control group design, the effects of the EDiT method on the teams’ collaboration are investigated based on three criteria: functional fulfillment, monetary return, and improvement in fields of potential. The analysis of the functional fulfillment of the developed bending machines shows that only the test groups were able to achieve comprehensive functional fulfillment. Moreover, the test groups achieve an average monetary return of €21, whereas the control group recorded a loss of €3. Finally, a subjective evaluation of the satisfaction in the fields of potential based on a 1 (not satisfied) to 5 (totally satisfied) scale shows an improvement in all measured fields of potential for the test groups compared to only one improved field of potential for the control group

Real-time OCT feedback-controlled RPE photodisruption in ex vivo porcine eyes using 8 microsecond laser pulses

Selective retinal pigment epithelium (RPE) photodisruption requires reliable real-time feedback dosimetry (RFD) to prevent unwanted overexposure. In this study, optical coherence tomography (OCT) based RFD was investigated in ex vivo porcine eyes exposed to laser pulses of 8 µs duration (wavelength: 532 nm, exposure area: 90 × 90 µm2, radiant exposure: 247 to 1975 mJ/µm2). For RFD, fringe washouts in time-resolved OCT M-scans (central wavelength: 870 nm, scan rate: 85 kHz) were compared to an RPE cell viability assay. Statistical analysis revealed a moderate correlation between RPE lesion size and applied treatment energy, suggesting RFD adaptation to inter- and intraindividual RPE pigmentation and ocular transmission

Gestión financiera y tratamiento contable tributario de las cuentas por pagar en la empresa “Maquirena S.A.C.” Lima - 2021

La investigación titulada “Gestión financiera y tratamiento contable tributario de las cuentas por pagar en la empresa Maquirena S.A.C. Lima - 2021”, tuvo como problema general ¿Qué relación existe entre la gestión financiera y el tratamiento contable tributario de las cuentas por pagar en la empresa “Maquirena S.A.C.” Lima - 2021? Lo cual nos permitió establecer el objetivo general que fue determinar la relación que existe entre de la gestión financiera y el tratamiento contable tributario de las cuentas por pagar en la empresa Maquirena S.A.C.” Lima – 2021. La investigación tuvo un enfoque cuantitativo, de tipo aplicada, diseño no experimental, nivel correlacional de corte transversal. La población estuvo conformada por 33 trabajadores de la empresa Maquirena, de la cual se trabajó con una muestra censal de los 33 trabajadores del área administrativa. Según los resultados obtenidos para el coeficiente de correlación Rho de Spearman existe una relación =,577** entre la gestión financiera y el tratamiento contable tributario de las cuentas por pagar, el cual es positiva moderada, con un valor de p= ,000 el cual es menor al nivel de significancia de 0,05 por el cual se rechaza la hipótesis nula y se acepta la hipótesis alterna. Se concluye que existe relación positiva entre la gestión financiera y el tratamiento contable tributario de las cuentas por pagar en la empresa Maquirena S.A.C. Lima – 2021. Esto permite decir que, cuanto mayor sea el nivel de la gestión financiera, mayor será el nivel del tratamiento contable tributario de las cuentas por pagar. Se recomienda al gerente de la empresa Maquirena S.A.C. aplicar una política de cumplimiento de pago hacia los proveedores y acreedores para evitar gastos innecesarios como los intereses, moras, multas y otros, que merma las utilidades del ejercicio

Expression of functional inhibitory neurotransmitter transporters GlyT1, GAT-1, and GAT-3 by astrocytes of inferior colliculus and hippocampus.

Neuronal inhibition is mediated by glycine and/or GABA. Inferior colliculus (IC) neurons receive glycinergic and GABAergic inputs, whereas inhibition in hippocampus (HC) predominantly relies on GABA. Astrocytes heterogeneously express neurotransmitter transporters and are expected to adapt to the local requirements regarding neurotransmitter homeostasis. Here we analyzed the expression of inhibitory neurotransmitter transporters in IC and HC astrocytes using whole-cell patch-clamp and single-cell reverse transcription-PCR. We show that most astrocytes in both regions expressed functional glycine transporters (GlyTs). Activation of these transporters resulted in an inward current (IGly) that was sensitive to the competitive GlyT1 agonist sarcosine. Astrocytes exhibited transcripts for GlyT1 but not for GlyT2. Glycine did not alter the membrane resistance (RM) arguing for the absence of functional glycine receptors (GlyRs). Thus, IGly was mainly mediated by GlyT1. Similarly, we found expression of functional GABA transporters (GATs) in all IC astrocytes and about half of the HC astrocytes. These transporters mediated an inward current (IGABA) that was sensitive to the competitive GAT-1 and GAT-3 antagonists NO711 and SNAP5114, respectively. Accordingly, transcripts for GAT-1 and GAT-3 were found but not for GAT-2 and BGT-1. Only in hippocampal astrocytes, GABA transiently reduced RM demonstrating the presence of GABAA receptors (GABAARs). However, IGABA was mainly not contaminated by GABAAR-mediated currents as RM changes vanished shortly after GABA application. In both regions, IGABA was stronger than IGly. Furthermore, in HC the IGABA/IGly ratio was larger compared to IC. Taken together, our results demonstrate that astrocytes are heterogeneous across and within distinct brain areas. Furthermore, we could show that the capacity for glycine and GABA uptake varies between both brain regions

Superposition for Lambda-Free Higher-Order Logic

We introduce refutationally complete superposition calculi for intentional and extensional clausal $\lambda$-free higher-order logic, two formalisms that allow partial application and applied variables. The calculi are parameterized by a term order that need not be fully monotonic, making it possible to employ the $\lambda$-free higher-order lexicographic path and Knuth-Bendix orders. We implemented the calculi in the Zipperposition prover and evaluated them on Isabelle/HOL and TPTP benchmarks. They appear promising as a stepping stone towards complete, highly efficient automatic theorem provers for full higher-order logic

Superposition for Lambda-Free Higher-Order Logic

International audienceWe introduce refutationally complete superposition calculi for intentional and extensional λ-free higher-order logic, two formalisms that allow partial application and applied variables. The calculi are parameterized by a term order that need not be fully monotonic, making it possible to employ the λ-free higher-order lexicographic path and Knuth-Bendix orders. We implemented the calculi in the Zipperposition prover and evaluated them on TPTP benchmarks. They appear promising as a stepping stone towards complete, efficient automatic theorem provers for full higher-order logic