227 research outputs found
Categoricity and Negation. A Note on Kripkeâs Affirmativism
We argue that, if taken seriously, Kripke's view that a language for science can dispense with a negation operator is to be rejected. Part of the argument is a proof that positive logic, i.e., classical propositional logic without negation, is not categorical
On the dimension of the space of integrals on coalgebras
We study the injective envelopes of the simple right -comodules, and their
duals, where is a coalgebra. This is used to give a short proof and to
extend a result of Iovanov on the dimension of the space of integrals on
coalgebras. We show that if is right co-Frobenius, then the dimension of
the space of left -integrals on is for any left
-comodule of finite support, and the dimension of the space of right
-integrals on is for any right -comodule of
finite support. If is a coalgebra, it is discussed how far is the dual
algebra from being semiperfect. Some examples of integrals are computed
for incidence coalgebras
SENSOR ARRAY ABLE TO DETECT AND RECOGNISE CHEMICAL WARFARE AGENTS
In this paper we studied a device based on array of six different sensors with surface acoustic wave for detections and recognition of three chemical warfare agents (chloropicrin, soman and lewisite). The sensors are âdelay lineâ type with a center frequency of 69.4 MHz. It presents an original algorithm to identify the nature and concentration of gas from a finite range of possible gases. Numerical program developed to implement this algorithm, provides to operators all the particulars of gas and an indicator of credibility of the results provided as a measure of the degree of disturbance of the signals received from sensors.SAW, chemical warfare agent, array of sensors, algorithm
Elastodynamic Griffith fracture on prescribed crack paths with kinks
We prove an existence result for a model of dynamic fracture based on Griffith\u2019s criterion in the case of a prescribed crack path with a kink
Existence for elastodynamic Griffith fracture with a weak maximal dissipation condition
We consider a model of elastodynamics with fracture evolution, based on energy-dissipation balance and a maximal dissipation condition. We prove an existence result in the case of planar elasticity with a free crack path, where the maximal dissipation condition is satisfied among suitably regular competitor cracks
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