95,503 research outputs found
F-Rationality of Rees Algebras
No full textAbstractIn this paper, using the notion of the tight integral closure, we will give a criterion for F-rationality of Rees algebras of m-primary ideals in a Cohen–Macaulay local ring. As its application, we prove the following results: (1) In dimension two, if A is F-rational and I is integrally closed, then the Rees algebra R(I) is F-rational. On the other hand, in higher dimensions, we construct many examples of Cohen–Macaulay, normal Rees algebras which are not F rational. (2) If both A and R(I) are F-rational, then so is the extended Rees algebra R′(I). (3) If R(I) is F-rational and a(G(I))≠−1, then A is F-rational.On the other hand, using resolution of singularities, we will prove that a two-dimensional rational singularity always admits F-rational Rees algebras. In particular, this theorem gives another way than that devised by Watanabe (1997, J. Pure Appl. Algebra122, 323–328) to construct counterexamples to the Boutot-type theorem for F-rational rings
Rees, R F, On23693
No full textThis record was harvested from a previous catalogue system and will be withdrawn in 2025. Information in this record may be superseded or incomplete. Visit this record in UMA's new catalogue at: https://archives.library.unimelb.edu.au/nodes/view/412664Surname: REES. Given Name(s) or Initials: R F. Military Service Number or Last Known Location: ON23693. Missing, Wounded and Prisoner of War Enquiry Card Index Number: 43947.229374
Item: [2016.0049.44926] "Rees, R F, On23693
Cotton Medal to Douglas Rees
No full textDouglas C. Rees, Roscoe Gilkey Dickinson
Professor of Chemistry at California Institute
of Technology and a Howard Hughes
Medical Institute investigator, is the winner
of the F. A. Cotton Medal for Excellence
in Chemical Research,
sponsored by the ACS
Texas A&M University
Section and the Texas
A&M department of
chemistry
On quotients of Rees algebras
No full textWe study ring theory properties of some quotients of Rees algebras, A(f) (a), that extend results of [2] and [3]. In particular, we use pullback constructions to describe the prime spectrum of A(f) (a). Some questions that we discuss in this paper remain open in general. (c) 2022 Elsevier B.V. All rights reserved
Rees Algebras of F-regular Type
No full textAbstractWe study the F-regularity of Rees algebras R(I)=A[It] in terms of the global F-regularity of the blowing-up X=ProjR(I) of SpecA. As it reads, global F-regularity is a global analog of strong F-regularity defined via splitting of Frobenius maps in prime characteristic, and these notions are extended to characteristic zero by reduction modulo p⪢0. We study in detail the case where (A,m) is a two-dimensional local ring and I is an m-primary ideal. In characteristic zero, the condition for R(I) to have F-regular type is described in terms of the dual graph of a resolution X̃ on which IOX̃ is invertible. We also prove some miscellaneous results concerning singularities of Rees algebras and extended Rees algebras of higher dimension
F-rationality of certain Rees algebras and counterexamples to “Boutot's Theorem” for F-rational rings
No full textAbstractF-rational rings are defined for rings of characteristic p > 0 using the Frobenius endomorphism and corresponds to rational singularities in characteristic 0. We study F-rationality of certain Rees algebras and prove that every Cohen-Macaulay local ring with isolated singularity and negative a-invariant has a Rees algebra which is F-rational. As a consequence, we find that “Boutot's Theorem” asserting that a pure subring of a rational singularity is a rational singularity is not true for a F-rational ring
The non--rational locus of Rees algebras
No full textIn this note, we give a description of the parameter test submodule of Rees
algebras. This, in turn, describes the non--rational locus.Comment: 5 page
Summary data for tracer gas dispersion tests for landfill methane emission monitoring at a UK landfill
No full textThis dataset supports the publications:
1) Rees-White, T. C., Mønster, J., Beaven R. P., Scheutz, C. (2018) Measuring methane emissions from a UK landfill sing the tracer dispersion method and the influence of operational and environmental factors https://doi.org/10.1016/j.wasman.2018.03.023
2) Matacchiera F, Manes C, Beaven RP, Rees-White TC, Boano F, Mønster J and Scheutz C (2018). AERMOD as a Gaussian dispersion model for planning tracer gas dispersion tests for landfill methane emission quantification https://doi.org/10.1016/j.wasman.2018.02.007
Contents
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This dataset contains the data discussed within the papers listed above and in certain Figures from the Rees-White paper.
The figures are as follows:
Fig. 3. Atmospheric pressure and wind speed during the period of August 5th to August 14th, 2014. Start and end times of each TDM experiment are given as vertical lines
Fig. 4. Incoming solar radiation and air temperature during the period of August 3th to August 14th, 2014. Start and end times of each TDM experiment are given as vertical lines
Fig. 6 (a to f). Methane emission data for each transect in a TDM with average overall emission and the 95% confidence interval. The name of the monitoring route used for a given transect is also shown
Fig. 7. Measured methane emissions vs. average wind speed for the six TDM trials. Linear regression is given (R2 = -0.82).
Fig. 8. Individual transect data from TDM2 shown against estimated wind speed, interpolated between measurement points. Data are colour coded to reflect the monitoring route used. a) shows data between 18:07 and 20:09, and b) 20:59 to 22:14.
Fig. 9. a) Average methane emission data from each monitoring route shown against measuring distance, b) Average methane emission rate from each monitoring route for a given TDM measured at different monitoring distances.
Geographic location of this data collection: University of Southampton, U.K.
Dataset available under a CC BY 4.0 licence
Publisher: University of Southampton, U.K.
Date: April 2018</span
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Interview of Martin Rees
No full textInterview of Lord Martin Rees the cosmologist and Master of Trinity College, Cambridge about his life and wor
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