منابع مشابه
Reliable algorithms for computing minimal dynamic covers
Minimal dimension dynamic covers play an important role in solving the structural synthesis problems of minimum order functional observers or fault detectors, or in computing minimal order inverses or minimal degree solutions of rational equations. We propose numerically reliable algorithms to compute two basic types of minimal dimension dynamic covers for a linear system. The proposed approach...
متن کاملInjective Envelopes and (Gorenstein) Flat Covers
In terms of the duality property of injective preenvelopes and flat precovers, we get an equivalent characterization of left Noetherian rings. For a left and right Noetherian ring R, we prove that the flat dimension of the injective envelope of any (Gorenstein) flat left R-module is at most the flat dimension of the injective envelope of RR. Then we get that the injective envelope of RR is (Gor...
متن کاملReliable algorithms for computing minimal dynamic covers for descriptor systems
Minimal dimension dynamic covers play an important role in solving the structural synthesis problems of minimum order functional observers or fault detectors, or in computing minimal order inverses or minimal degree solutions of rational equations. We propose numerically reliable algorithms to compute two basic types of minimal dimension dynamic covers for a linear system. The proposed approach...
متن کاملMinimal Covers of Formal Languages
Let L1; L2 be languages. If L1 L2, then we say that L2 covers L1. Let C;D be classes of languages over . We call a cover L2 2 C of L1 a C-minimal cover with respect to D if, for all L0 2 C, L1 L0 L2 implies L2 L0 2 D. We examine in detail the particular cases of minimal regular covers and minimal context-free covers, both with respect to nite languages. The closure properties of the class of la...
متن کاملMinimal Covers and Arithmetical Sets1
If a and b are degrees of unsolvability, a is called a minimal cover of b if b<a and no degree c satisfies b<c<a. The degree a is called a minimal cover if it is a minimal cover of some degree b. We prove by a very simple argument that 0" is not a minimal cover for any n. From this result and the axiom of Borel determinateness (BD) we show that the degrees of arithmetical sets (with their usual...
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ژورنال
عنوان ژورنال: Journal of Pure and Applied Algebra
سال: 2020
ISSN: 0022-4049
DOI: 10.1016/j.jpaa.2019.106280