75
75

Sep 23, 2013
09/13

by
Kevin Tucker

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In this article, we study the jumping numbers of an ideal in the local ring at rational singularity on a complex algebraic surface. By understanding the contributions of reduced divisors on a fixed resolution, we are able to present an algorithm for finding of the jumping numbers of the ideal. This shows, in particular, how to compute the jumping numbers of a plane curve from the numerical data of its minimal resolution. In addition, the jumping numbers of the maximal ideal at the singular...

Source: http://arxiv.org/abs/0801.0734v2

54
54

Sep 18, 2013
09/13

by
Kevin Tucker

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We show that all integrally closed ideals on log terminal surfaces are multiplier ideals by extending an existing proof for smooth surfaces.

Source: http://arxiv.org/abs/0809.3043v1

44
44

Sep 22, 2013
09/13

by
Kevin Tucker

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Suppose R is a Noetherian local ring with prime characteristic p>0. In this article, we show the existence of a local numerical invariant, called the F-signature, which roughly characterizes the asymptotic growth of the number of splittings of the iterates of the Frobenius endomorphism of R. This invariant was first formally defined by C. Huneke and G. Leuschke and has previously been shown to exist only in special cases. The proof of our main result is based on the development of certain...

Source: http://arxiv.org/abs/1103.4173v1

9
9.0

Apr 21, 2021
04/21

by
Kevin Tucker (tuckerkm)

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Customized version of http://www.thingiverse.com/thing:53451 Created with Customizer! http://www.thingiverse.com/apps/customizer/run?thing_id=53451

Topics: thingiverse, Parts, stl, customized

6
6.0

Jan 16, 2021
01/21

by
Kevin Tucker (kevtucker)

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Remix of https://www.thingiverse.com/thing:1524972 I had trouble with bottom of the original STL so cut it off in MeshMixer and prints fine now on Original Prua MK2S at 0.2mm Layer Height.

Topics: 3D Printing, stl, thingiverse

8
8.0

Jan 13, 2021
01/21

by
Kevin Tucker (kevtucker)

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Remix of original test as I forgot to fillet edges in other one :)

Topics: spinner, thingiverse, fidget_hand_Spinner, stl, Toys & Games, fidget_spinner, fidget_spiner

6
6.0

Jan 17, 2021
01/21

by
Kevin Tucker (kevtucker)

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Covers for the M6 screws for Zaribo build.

Topics: 3D Printer Parts, stl, thingiverse

5
5.0

Jan 21, 2021
01/21

by
Kevin Tucker (kevtucker)

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Stand for e-liquids 10ml UK size. 6 holes for 20mm bottle size and 2 holes for 22mm bottle size.

Topics: Hobby, stl, thingiverse

6
6.0

Jan 17, 2021
01/21

by
Kevin Tucker (kevtucker)

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This is a Multi Colour Print using PrusaControl. Model is made from a SVG then extruded in Fusion 360 up to 2mm high. Then sliced in PrusaControl to change the Green to Black at 1.20mm high by using the Colour change option (M600)

Topics: thingiverse, Yoda, dual_extrusion, prusa_i3, 3D Printing, stl, star_wars

6
6.0

Jan 17, 2021
01/21

by
Kevin Tucker (kevtucker)

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This is a Multi Colour Print using PrusaControl. Model is made from a SVG then extruded in Fusion 360 up to 2mm high. Then sliced in PrusaControl to change the White to Black at 1.20mm high by using the Colour change option (M600)

Topics: Stormtrooper, thingiverse, prusa_i3_mk2, prusacontrol, 3D Printing, stl

9
9.0

Apr 21, 2021
04/21

by
Kevin Tucker (tuckerkm)

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Customized version of http://www.thingiverse.com/thing:53451 Created with Customizer! http://www.thingiverse.com/apps/customizer/run?thing_id=53451

Topics: thingiverse, Parts, stl, customized

3
3.0

Apr 20, 2021
04/21

by
Kevin Tucker (kevtucker)

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48mm Trinocular Microscope 7x45x Lens Cap. Just a spare lens cap or incase you lost the original.

Topics: thingiverse, stl, Electronics

8
8.0

Jan 12, 2021
01/21

by
Kevin Tucker (kevtucker)

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Testing a Spinner

Topics: spinner, thingiverse, fidget_hand_Spinner, stl, Toys & Games, fidget_spinner

3
3.0

Apr 21, 2021
04/21

by
Kevin Tucker (kevtucker)

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Basic Dish for testing a 3D Roughing and Finishing Cut with Dremel CNC

Topics: thingiverse, stl, dish, Sculptures, dremel, cnc

5
5.0

Mar 2, 2021
03/21

by
Kevin Tucker (kevtucker)

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75mm x 75mm First Layer Calibration Square. I use this to calibrate the Live-Z height on my Original Prusa MK2.5. Just slice it at 0.2mm layer height and use it for different materials to dial in the perfect height.

Topics: thingiverse, stl, 3D Printing

6
6.0

Jan 16, 2021
01/21

by
Kevin Tucker (kevtucker)

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For Prusa bed calibration. Measures 190 x 240 so not the entire bed.

Topics: 3D Printing, stl, thingiverse

7
7.0

Jan 17, 2021
01/21

by
Kevin Tucker (kevtucker)

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This is a Multi Colour Print using PrusaControl. Model is made from a SVG then extruded in Fusion 360 up to 2mm high. Then sliced in PrusaControl to change the White to Black at 1.20mm high by using the Colour change option (M600)

Topics: prusa_i3, bob, thingiverse, reggae, Bob_Marley, Marley, 3D Printing, stl

9
9.0

Apr 21, 2021
04/21

by
Kevin Tucker (tuckerkm)

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Customized version of http://www.thingiverse.com/thing:53451 Created with Customizer! http://www.thingiverse.com/apps/customizer/run?thing_id=53451

Topics: thingiverse, Parts, stl, customized

4
4.0

Jun 29, 2018
06/18

by
Thomas Polstra; Kevin Tucker

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We present a unified approach to the study of Hilbert-Kunz multiplicity, F-signature, and related limits governed by Frobenius and Cartier linear actions in positive characteristic commutative algebra. We introduce general techniques that give vastly simplified proofs of existence, semicontinuity, and positivity. Furthermore, we give an affirmative answer to a question of Watanabe and Yoshida allowing the F-signature to be viewed as the infimum of relative differences in the Hilbert-Kunz...

Topics: Commutative Algebra, Mathematics

Source: http://arxiv.org/abs/1608.02678

40
40

Sep 17, 2013
09/13

by
Karl Schwede; Kevin Tucker

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We derive transformation rules for test ideals and $F$-singularities under an arbitrary finite surjective morphism $\pi : Y \to X$ of normal varieties in prime characteristic $p > 0$. The main technique is to relate homomorphisms $F_{*} O_{X} \to O_{X}$, such as Frobenius splittings, to homomorphisms $F_{*} O_{Y} \to O_{Y}$. In the simplest cases, these rules mirror transformation rules for multiplier ideals in characteristic zero. As a corollary, we deduce sufficient conditions which imply...

Source: http://arxiv.org/abs/1003.4333v3

47
47

Sep 18, 2013
09/13

by
Karl Schwede; Kevin Tucker

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Suppose that $\pi \: Y \to X$ is a finite map of normal varieties over a perfect field of characteristic $p > 0$. Previous work of the authors gave a criterion for when Frobenius splittings on $X$ (or more generally any $p^{-e}$-linear map) extend to $Y$. In this paper we give an alternate and highly explicit proof of this criterion (checking term by term) when $\pi$ is tamely ramified in codimension 1. Some additional examples are also explored.

Source: http://arxiv.org/abs/1201.5973v1

46
46

Sep 21, 2013
09/13

by
Karl Schwede; Kevin Tucker

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Test ideals were first introduced by Mel Hochster and Craig Huneke in their celebrated theory of tight closure, and since their invention have been closely tied to the theory of Frobenius splittings. Subsequently, test ideals have also found application far beyond their original scope to questions arising in complex analytic geometry. In this paper we give a contemporary survey of test ideals and their wide-ranging applications.

Source: http://arxiv.org/abs/1104.2000v2

76
76

Sep 23, 2013
09/13

by
Karl Schwede; Kevin Tucker

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Let $X$ be a projective Frobenius split variety over an algebraically closed field with splitting $\theta : F_* \O_X \to \O_X$. In this paper we give a sharp bound on the number of subvarieties of $X$ compatibly split by $\theta$. In particular, suppose $\sL$ is a sufficiently ample line bundle on $X$ (for example, if $\sL$ induces a projectively normal embedding) with $n = \dim H^0(X, \sL)$. We show that the number of $d$-dimensional irreducible subvarieties of $X$ that are compatibly split by...

Source: http://arxiv.org/abs/0903.4112v3

40
40

Sep 23, 2013
09/13

by
Karl Schwede; Kevin Tucker

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Given an ideal $a \subseteq R$ in a (log) $Q$-Gorenstein $F$-finite ring of characteristic $p > 0$, we study and provide a new perspective on the test ideal $\tau(R, a^t)$ for a real number $t > 0$. Generalizing a number of known results from the principal case, we show how to effectively compute the test ideal and also describe $\tau(R, a^t)$ using (regular) alterations with a formula analogous to that of multiplier ideals in characteristic zero. We further prove that the $F$-jumping...

Source: http://arxiv.org/abs/1212.6956v2

105
105

Sep 23, 2013
09/13

by
Manuel Blickle; Karl Schwede; Kevin Tucker

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This paper contains a number of observations on the {$F$-signature} of triples $(R,\Delta,\ba^t)$ introduced in our previous joint work. We first show that the $F$-signature $s(R,\Delta,\ba^t)$ is continuous as a function of $t$, and for principal ideals $\ba$ even convex. We then further deduce, for fixed $t$, that the $F$-signature is lower semi-continuous as a function on $\Spec R$ when $R$ is regular and $\ba$ is principal. We also point out the close relationship of the signature function...

Source: http://arxiv.org/abs/1111.2762v2

46
46

Jul 20, 2013
07/13

by
Manuel Blickle; Karl Schwede; Kevin Tucker

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We generalize $F$-signature to pairs $(R,D)$ where $D$ is a Cartier subalgebra on $R$ as defined by the first two authors. In particular, we show the existence and positivity of the $F$-signature for any strongly $F$-regular pair. In one application, we answer an open question of I. Aberbach and F. Enescu by showing that the $F$-splitting ratio of an arbitrary $F$-pure local ring is strictly positive. Furthermore, we derive effective methods for computing the $F$-signature and the $F$-splitting...

Source: http://arxiv.org/abs/1107.1082v2

66
66

Jul 20, 2013
07/13

by
Karl Schwede; Kevin Tucker; Wenliang Zhang

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Suppose $(X, \Delta)$ is a log-$\bQ$-Gorenstein pair. Recent work of M. Blickle and the first two authors gives a uniform description of the multiplier ideal $\mJ(X;\Delta)$ (in characteristic zero) and the test ideal $\tau(X;\Delta)$ (in characteristic $p > 0$) via regular alterations. While in general the alteration required depends heavily on $\Delta$, for a fixed Cartier divisor $D$ on $X$ it is straightforward to find a single alteration (e.g. a log resolution) computing $\mJ(X; \Delta...

Source: http://arxiv.org/abs/1107.4059v2

52
52

Jul 20, 2013
07/13

by
Manuel Blickle; Karl Schwede; Kevin Tucker

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For a normal F-finite variety $X$ and a boundary divisor $\Delta$ we give a uniform description of an ideal which in characteristic zero yields the multiplier ideal, and in positive characteristic the test ideal of the pair $(X,\Delta)$. Our description is in terms of regular alterations over $X$, and one consequence of it is a common characterization of rational singularities (in characteristic zero) and F-rational singularities (in characteristic $p$) by the surjectivity of the trace map...

Source: http://arxiv.org/abs/1107.3807v3

10
10.0

Jun 30, 2018
06/18

by
Zsolt Patakfalvi; Karl Schwede; Kevin Tucker

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These are notes for the Bootcamp volume for the 2015 AMS Summer Institute in Algebraic Geometry. They are based on earlier notes for the "Positive Characteristic Algebraic Geometry Workshop" held at University of Illinois at Chicago in March 2014.

Topics: Mathematics, Commutative Algebra, Algebraic Geometry

Source: http://arxiv.org/abs/1412.2203

7
7.0

Jun 29, 2018
06/18

by
Javier Carvajal-Rojas; Karl Schwede; Kevin Tucker

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We prove that the local etale fundamental group of a strongly $F$-regular singularity is finite (and likewise for the \'etale fundamental group of the complement of a codimension $\geq 2$ set), analogous to results of Xu and Greb-Kebekus-Peternell for KLT singularities in characteristic zero. In fact our result is effective, we show that the reciprocal of the $F$-signature of the singularity gives a bound on the size of this fundamental group. To prove these results and their corollaries, we...

Topics: Commutative Algebra, Algebraic Geometry, Mathematics

Source: http://arxiv.org/abs/1606.04088

9
9.0

Jun 30, 2018
06/18

by
Tommaso de Fernex; Roi Docampo; Shunsuke Takagi; Kevin Tucker

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We show that the reduction to positive characteristic of the multiplier ideal in the sense of de Fernex and Hacon agrees with the test ideal for infinitely many primes, assuming that the variety is numerically Q-Gorenstein. It follows, in particular, that this reduction property holds in dimension 2 for all normal surfaces.

Topics: Mathematics, Algebraic Geometry

Source: http://arxiv.org/abs/1401.7946

5
5.0

Jun 29, 2018
06/18

by
Bhargav Bhatt; Javier Carvajal-Rojas; Patrick Graf; Karl Schwede; Kevin Tucker

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We prove that a strongly $F$-regular scheme $X$ admits a finite, generically Galois, and \'etale-in-codimension-one cover $\widetilde X \to X$ such that the \'etale fundamental groups of $\widetilde X$ and $\widetilde X_{reg}$ agree. Equivalently, every finite \'etale cover of $\widetilde X_{reg}$ extends to a finite \'etale cover of $\widetilde X$. This is analogous to a result for complex klt varieties by Greb, Kebekus and Peternell.

Topics: Commutative Algebra, Algebraic Geometry, Mathematics

Source: http://arxiv.org/abs/1611.03884

249
249

Dec 24, 2019
12/19

by
Kevin Tucker

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"Gathered Remains is the definitive tour de force for our times. With writing that flows like a wind-kissed field, Tucker's impeccable reason and rich scholarship forges something unique: inspiration in the face of soul-breaking truth. In so doing, we are provided with a map of reality, and critically, a way to live in harmony with nature again." - G.A. Bradshaw PhD PhD, Author of Carnivore Minds "Kevin Tucker's writings have been absolutely essential in the development of an...

Topics: Primitivism, Primitivist, Anarchy, Anarchist, Anarchism, Wild, Wildness, Green, Natural, Nature,...

1,075
1.1K

Nov 27, 2009
11/09

by
Kevin Tucker

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An anti-authoritarian analysis of the consequences of domestication, by Kevin Tucker.

Topics: primal anarchy, species traitor, kevin tucker, anarcho-primitivism, green anarchy,...

17
17

Feb 25, 2018
02/18

by
Kevin Tucker

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Photos taken of Bierley by Kevin Tucker using Mavic Pro Drone.

Topics: Bierley, Bradford, BD4, Ferrand, Hambledon

25
25

Mar 27, 2022
03/22

by
Kevin Tucker

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Cull of Personality is the story of civilization, showing how a conquering society, so depraved of meaning, will seek to destroy the world to find its purpose. And when it is fought and resisted, even the coping mechanism of those who have fought it is still up for sale. ... In April 2018, a Canadian man shot and killed the Shipibo-Conibo healer, Olivia Arevalo. He had been going to the Peruvian Amazon on and off for years, seeking one thing: ayahausaca. In his story, he wanted to become a...

Topics: Black and Green Press, Anarchy, Anarchist, Anarchism, Green Anarchy, Anarcho-Primitivism,...

38
38

May 3, 2021
05/21

by
Kevin Tucker

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Thesen zum Untergang der Zivilisation oder: Wie ich lernte, mich nicht mehr zu sorgen und den kommenden Zusammenbruch zu begrüssen Ich sehe den Untergang der Zivilisation als unvermeidlich und arbeite darum sowohl darauf hin, den Kollaps zu unterstützen, als ihn auch voranzutreiben und dafür brauche ich keine Rechtfertigungen. Klassenkampf, Kommodifizierung und die modernisierte Gesellschaft Es scheint offensichtlich, dass eine Revolte, die darauf ausgerichtet ist, das gigantische Biest der...

Topics: Primitivismus, Zivilisationskritik, Individualismus, Technologie, Technik, Industrie, Klassenkampf,...

30
30

Mar 27, 2022
03/22

by
Kevin Tucker

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For wildness and anarchy is a collection of essays from primal anarchist writer Kevin Tucker expanding upon the anarchist critiques of civilization from a multitude of perspectives. Taking an in-depth look at the failures of domestication and revolution, the essays in this volume turn towards a reawakening of the "primal anarchy" of our nomadic hunter-gatherer ancestors and relatives. The essays focus on challenging traditional anarchist and Leftist assumptions about the nature of...

Topics: Black and Green Press, Anarchy, Anarchist, Anarchism, Green Anarchy, Anarcho-Primitivism,...

794
794

Apr 20, 2015
04/15

by
Black and Green Press, Kevin Tucker, Ryan Morgan

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The Suffocating Void: Domestication and Pathological Distraction - Kevin Tucker From Black and Green Review no. 1, Spring 2015 . Read by Ryan Morgan of Paper Crane Audio . The Suffocating Void is an anarcho-primitivist critique of the role social networking has played in the advancement of civilization through late modernity. An anti-technological look at how the widely unnoticed revolution of the digital/interface age has furthered the domestication process leading us further down the path of...

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Topics: Kevin Tucker, The Suffocating Void, Anarcho-Primitivism, Green Anarchy, Anti-civ, Anti-technology,...