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On projective covers of semimodules and perfect semirings
Journal of Algebra and Its Applications, 2014We consider two natural concepts of "perfectness" in a semiring context: the perfectness in terms of projective covers, and the perfectness in Bass's sense. For both cases we show that the class of right (left) perfect semirings coincides with the class of right (left) perfect rings; in particular, we completely confirm Conjecture of [Y.
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A Note on the Covering of Projective Surfaces
Results in Mathematics, 2008Let X be a weakly 1-complete surface and (Y, π) be a, possibly ramified, Riemann domain over X. If \(H^1(Y,{\mathcal{O}}^*) = 0\), then Y is Stein and \(H^2(Y, {\mathbb{Z}}) = 0\).
A. D. R. Choudary, V. Vâjâitu
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Projective covers as subquotients of enlargements
Israel Journal of Mathematics, 1973We show that not only completions of systems in various senses but also projective covers in the category of compact Hausdorff spaces may be obtained as subquotients of enlargements.
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Covering groups and projective representations
1992In order to deduce Theorem 1.18 from the special case established in the last chapter, we will need to exploit a relationship between characters of tori in G and representations of G. This relationship is most natural when it is formulated in terms of certain coverings of the tori related to “ρ-shifts” for G (see for example Theorem 1.37 or Theorem 6.8
Jeffrey Adams +2 more
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A Note on Counting Connected Graph Covering Projections
SIAM Journal on Discrete Mathematics, 1998zbMATH Open Web Interface contents unavailable due to conflicting licenses.
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Projective Groups and Frattini Covers
1986The absolute Galois group of a PAC field is projective (Theorem 10.17). This chapter includes a converse (Corollary 20.16): If G is a projective group, then there exists a PAC field K such that G (K) ≅ G. Projective groups also appear as the universal Frattini covers of profinite groups (Proposition 20.33).
Michael D. Fried, Moshe Jarden
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Directed fibrations and covering projections
Publicationes Mathematicae Debrecen, 2009Summary: In this note a notion of Hurewicz fibration in the category d{\textbf{Top}} of directed spaces in the sense of \textit{M. Grandis} [Cah. Topol. Géom. Différ. Catég. 44, No.~4, 281--316 (2003; Zbl 1059.55009)] is defined. The directed homotopy lifting property is characterized by means of lifting pairs.
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Projective covers over local rings
Annali Di Matematica Pura Ed Applicata, 2021Alberto Facchini
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This activity helps students learn about and draft a cover letter for a job or internship. The focus is on Earth Science students and jobs, but the activity is easily adaptable for other majors/careers. The activity is scaffolded and includes journaling and self-reflection, peer reviews, giving and receiving feedback, group discussions, and writing.
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Relating foliage and crown projective cover in Australian tree stands
Agricultural and Forest Meteorology, 2018Peter Scarth +2 more
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