Publications
Stefan Kohl
Journal Articles
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(With Leyli Jafari and Eamonn O'Brien:) Automorphism group orbits on finite simple groups.
Comm. Algebra 49 (2021), No. 8, 3294-3300.
DOI: 10.1080/00927872.2021.1894166.
MR4283148,
Zbl 07405278.
Download: PDF.
Cited by [Li, Zhu 2024].
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(With Leyli Jafari and Mohammad Zarrin:) A classification of the finite non-solvable minimal non-CA-groups.
J. Algebra Appl 20 (2021), No. 11, 2150203.
DOI: 10.1142/S0219498821502030.
MR4328094,
Zbl 07420038.
Download: PDF.
Cited by [Liu, Miao, Wang 2022].
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(With Leyli Jafari:) Simple groups the derived subgroups of all of whose subgroups are TI-subgroups.
Comm. Algebra 47 (2019), No. 11, 4676-4683.
DOI: 10.1080/00927872.2019.1588979.
MR3991042,
Zbl 1480.20046.
Download: PDF.
Cited by [Meng, Lu, Zhang 2023].
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The Collatz conjecture in a group theoretic context.
J. Group Theory 20 (2017), No. 5, 1025-1030.
DOI: 10.1515/jgth-2017-0012,
MR3692062,
Zbl 1400.20022.
Download: PDF.
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Simple groups generated by involutions interchanging residue classes modulo lattices in Zd.
J. Group Theory 16 (2013), No. 1, 81-86.
DOI: 10.1515/jgt-2012-0031.
MR3008313,
Zbl 1287.20041.
Download: PDF DVI.
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A simple group generated by involutions interchanging residue classes of the integers.
Math. Z. 264 (2010), No. 4, 927-938.
DOI: 10.1007/s00209-009-0497-8.
MR2593301,
Zbl 1210.20026.
Download: PDF DVI.
Cited by [Hines 2022].
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Algorithms for a class of infinite permutation groups.
J. Symb. Comput. 43 (2008), No. 8, 545-581.
DOI: 10.1016/j.jsc.2007.12.001.
MR2415857,
Zbl 1155.20003.
Download: PDF DVI.
Cited by [Tuncer, Kurum 2020].
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On conjugates of Collatz-type mappings.
Int. J. Number Theory 4 (2008), No. 1, 117-120.
DOI: 10.1142/S1793042108001237.
MR2387919,
Zbl 1157.11306.
Download: PDF DVI.
Cited by [Sultanow, Volkov, Cox 2017].
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Wildness of iteration of certain residue-class-wise affine mappings.
Adv. in Appl. Math. 39 (2007), No. 3, 322-328.
DOI: 10.1016/j.aam.2006.08.003.
MR2352043,
Zbl 1146.11015.
Download: PDF DVI.
Cited by [Michel 2015],
[Aaronson, Heule, Yolcu 2021,
2023].
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Classifying finite simple groups with respect to the number of orbits under the action of the automorphism group.
Comm. Algebra 32 (2004), No. 12, 4785-4794.
DOI: 10.1081/AGB-200039279.
MR2111596,
Zbl 1077.20023.
Download: PDF DVI.
Supplementary tables: PDF DVI;
updated version, incorporating the results of a larger
MAGMA computation run by
Eamonn O'Brien in December 2019
and some further results obtained by Frank Lübeck
and Robert A Wilson in January 2020: PDF.
GAP routines used for the paper: autorb.g.
Cited by [Ashrafi, Shi 2008],
[Bastos, Dantas 2016],
[Bastos, Dantas, Garonzi 2017],
[Bastos, Dantas 2018],
[Sambale 2018],
[Bastos, Dantas, de Melo 2020],
[Bastos, Dantas, de Melo 2021],
[Bors, Giudici, Praeger 2023].
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Counting the orbits on finite simple groups under the action of the automorphism group -
Suzuki groups vs. linear groups.
Comm. Algebra 30 (2002), No. 7, 3515-3532.
DOI: 10.1081/AGB-120004501.
MR1915010,
Zbl 1011.20015.
Erratum.
Download: PDF DVI.
Cited by [Ashrafi, Shi 2005],
[Ashrafi, Shi 2008],
[Butron 2011],
[Bastos, Dantas 2018],
[Bors, Giudici, Praeger 2023].
Theses
GAP Packages
Refereed
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RCWA.
Residue-class-wise affine groups. GAP package. 2005.
Current version: 4.7.1 (released 06/12/2022).
For a longer description and download, see here.
Cited by [Bond 2022].
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FactInt.
Advanced methods for factoring integers. GAP package. 1999.
Current version: 1.6.3 (released 15/11/2019).
For a longer description and download, see here.
Other
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ResClasses.
Set-theoretic computations with residue classes. GAP package. 2004.
Current version: 4.7.3 (released 27/07/2022).
For a longer description, see here.
Preprints
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On the cycle structure of products of two class transpositions. 5 pages, 2009, revised 2011.
Download: PDF.
Short Notes
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Two invariants of residue-class-wise affine permutations of the integers. 6 pages, 2006.
Download: PDF PS DVI.
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A reformulation of the 3n+1 conjecture in terms of a mapping from the free monoid of rank 2 to the positive integers. 3 pages, 2007.
Download: PDF PS DVI.
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Graph theoretical criteria for the wildness of residue-class-wise affine permutations. 4 pages, 2007.
Download: PDF PS DVI.
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On Carmichael numbers with 3 factors. 3 pages, 2006.
Download: PDF PS DVI.
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A bound on the order of the outer automorphism group of a finite simple group of given order. 2 pages, 2003.
Download: PDF PS DVI.
Cited by [Luks, Miyazaki 2011],
[Bamberg, Li, Swartz 2017]
(arXiv version),
[Glasby, Praeger, Rosa, Verret 2018]
(arXiv version),
[Bors, Giudici, Praeger 2019],
[Bors 2019],
[Aivazidis, Mueller 2021]
(Oberwolfach Preprint version,
arXiv version),
[Guo, Guo, Ryabov, Vasil'ev 2021],
[Bachraty, Conder, Verret 2022]
(arXiv version),
[Lucchini, Spiga 2022]
(arXiv version),
[Lucchini, Thakkar 2023]
(arXiv version).
Other
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I am one of the many authors of the computer algebra system GAP.
A list of my contributions to the GAP Library can be found here.
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Since November 2012, I am an active contributor to MathOverflow.
In particular, I have answered there questions of many colleagues on various different topics.
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I am a reviewer for MathSciNet.
A list of papers I have written reviews for can be found here.
(Accessing that page requires a subscription to MathSciNet.
The choice of papers is by the editors.)
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Various questions of mine have been published in the Kourovka Notebook,
namely Problems 17.57, 17.58, 17.59, 17.60, 17.61, 18.47, 18.48, 18.49 (solved by J. Konig), 18.50, 18.51, 19.45, 19.46, 20.44 and 20.45 --
and one question of mine has appeared in Advances in Group Theory and Applications, 2 (2016), 139-140.
See here.
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This picture I created has made it on the conference poster of the
AMSI/AustMS workshop "Geometry and Analysis",
Flinders University, Adelaide, September 25 - September 27, 2015.
I am a moderator on MathOverflow (elected in April 2021).
Since many years, I am a member of the GAP Support Group.
For my profile on ResearchGate, see here.
There is a list of BibTeX entries for my refereed publications and theses.
I try to follow the recommendations of the IMU as given here.