Projects

- Algorithmic implementations of Endomorphism rings of supersingular Drinfeld Modules. Mainly written reports. (August 2005)
- Algorithmic implementations of Brauer invariants. Mainly written reports. (September 2005)
- Junior member of FP6 Research and Training Network "Galois Theory and Explicit Methods" (GTEM). Written reports and implementations in Magma and SAGE. (October 2006 to October 2010)- Toolkit for security tests for Elliptic Curve Cryptography, written both in C++ (using NTL) and Magma. Part of Brainpool for EU passport standards. (December 2006)
- Website construction in PHP. Created http://www.tzimakos.gr in PHP. (January 1998 to present)
- AutoWikiBrowser, Wikipedia specialised browser that uses .NET. Developer. Contributions in C# and Visual Basic for plugins (October 2007 to present)

Undergraduate Courses

Here is a list of the courses I have attended as an undergraduate student in the University of Crete (1997-2003). The maximum grade is ten (10), the passing grade is five (5) and the scaling is the following: 8.5-10 excellent, 6.5-8.49 very good, 5-6.49 good. The grade point average (GPA) of graduation is computed according to the Ministerial Decree F-141/B3/2166 (FEK 308/18-6-87) for all Greek Universities.

 

Computer Programming	10
Algebra I	9
English I	7.5
English II	7.5
English III	7.5
Calculus I	7.5
Introduction to Set Theory	7.5
Linear Algebra I	7
English IV	6.5
Probability Theory	6
Introduction to Analysis II	6
Introduction to Analysis I	5
Calculus II	5
Calculus III	5
Analytical Geometry - Complex Numbers	5
Physics I	5
Theory of Recursive Functions	10
Number Theory	9
Special Topics: Computation Theory	9
Mathematics Education	7
Discrete Mathematics	5
Topics in Analysis: The Problem Seminar	9
Ordinary Differential Equations	7.5
Topics in Algebra: Cryptology	10
Rings and Modules Theory	10
Topics in Algebra: Symbolic Computation	9.5
Topics in Algebra: Applied Algebra	8.5
Topics in Algebra: Quadratic Number Fields	8
Linear Algebra II	7.5
Group Theory	7.5
Fields Theory	7.5
Topics in Algebra: Linear Algebra & Modules	6
Topics in Applied Mathematics: Algorithms and Complexity Theory	9.5
Topics in Probability and Statistics: Descriptive Statistics	8
Numerical Analysis	6.5
Introduction to Pedagogy	8
School Pedagogy	8
Supportive and Compensative Education	6.5
Algebra I (Graduate)	9
Numerical Analysis (Graduate)	8
Algebraic Geometry (Graduate)	7
Coding (Graduate)	7
Functional Analysis (Graduate)	6
On-job training in Education	8.5
Diploma Thesis	9

Teaching Experience (short version)

As undergraduate and graduate student at the Univ. of Crete I worked as an assistant to the following courses.

2 semesters Algebra I

1 semester Linear Algebra I

1 semester Introduction to Computing

1 semester Applied Algebra

2 semesters Number Theory

1 semester Rings and Modules Theory

1 semester Group Theory

2 semesters Cryptology

1 semester Symbolic Computations


During my phD I assisted the following courses:

1 semester Analysis II at the University of Duisburg-Essen

2 semesters Algebra I at the Carl von Ossietzky University of Oldenburg

1 semester Algorithmic Number Theory at the Carl von Ossietzky University of Oldenburg

Talks

2011

Semiautomated editing in Wikipedia: The AutoWikiBrowser case (in English, 18 slides)
(abstract missing)

Lattices, elliptic curves over the complex numbers and isogeny graphs (in English, 24 pages)
(abstract missing)

DLP: From RSA to ECDLP and HCDLP (in German and English, 26 slides)
We discuss the difficulty of the discrete logarithm problem in various finite fields. We also examine various attacks on ECDLP and focus on the isogeny attack.

2009

The discrete logarithm problem on isogenous hyperelliptic curves of genus 2 (in English, 53 slides)
In 2005, Jao, Miller, and Venkatesan proved that the DLP of elliptic curves with the same endomorhism ring is random reducible under the GRH. In this talk, we discuss a possible generalization of this result to hyperelliptic curves of genus 2 (and 3) defined over a finite field and show the difficulties involved. First, we explain the role of the endomorphism rings of the Jacobian and the polarization. Following the work of Jao, Miller and Venkatesan, we construct isogeny graphs for genus 2 curves. Specifically, we discuss the connection between isogenies and ideal classes in the Jacobian of these curves. This project is research in progress and we describe the current status of this research.

The DLP on Curves with the same endomorphism ring: The genus 2 case (in English and partially in German, 49 slides)
We try to extend the result we presented in our last talk for higher genus curves. We give some background on the arithmetic of curves of high genus and discuss the discrete logarithm problem (DLP) in the divisor class group for curves over finite fields with Jacobian varieties having the same ring of endomorphisms. We strict ourselves to the genus 2 case with Jacobian of CM type and we present the work we have done so far. Finally, we explain which phenomena can occur for curves of genus 3.

The DLP on Curves with the same endomorphism ring: The genus 1 case (in English, 48 slides)
We consider elliptic curves with the same order over a finite filed and the same endomorphism ring. We ask whether the discrete logarithm problem has the same complexity. We present a result of Jao, Miller and Venkatesan who proved that the answer to our question is positive  under Generalised Riemann Hypothesis. Possible generalisations on curves of higher genus will be discussed in a second talk.

The DLP on Elliptic and Hyperelliptic Curves with the same endomorphism ring (in English, 39 slides)
We ask whether the discrete logarithm problem (DLP) in the divisor class group has the same complexity for all curves over finite fields with Jacobian varieties having the same ring of endomorphisms. We present a result of Jao, Miller and Venkatesan who proved that the answer to our question is positive for elliptic curves. We try to use the same methods to extend the result to the genus 2 case in the case that the Jacobian is of CM type and we present the work we have done so far. Finally, we explain which phenomena can occur for curves of genus 3.

2008

Iwasawa's theorem (in English, 15 pages)
We prove the Iwasava's Theorem, which describes the behaviour of the class number in an extension of a finite field.
[dvi] [ps] [pdf]

Arithmetic of Quaternion Algebras: Orders and Ideals (in English, 17 pages)
The basics on the arithmetic on quaternion algebras is introduced: (maximal) orders, (principal) ideals, (reduced) norm/discriminant, ideal classes, etc.
[dvi] [ps] [pdf]

The DLP on Elliptic Curves with the same order (in English, 20 pages)
We ask whether the discrete logarithm problem (DLP) has the same difficulty for all curves with the same order over a finite field. We present the result of Jao, Miller and Venkatesan who proved that the answer to our question is positive if you limit ourselves to curves with the same endomorphism ring.
[ps] [pdf]

2007

The Tensor Product Theorem (in English, 11 pages)
The Tensor Product Theorem from Flath asserts that if A is the adele ring of a global field F and G is a reductive algebraic group over F, then G(A) decomposes into a "restricted tensor product" of representations of the groups G(F_υ). We give a proof of the theorem.
[dvi] [ps] [pdf]

2006

Modular forms of weight 1 (in English, 22 pages)
We study modular forms and Galois representations over finite and fields and over the complex numbers. We give the proof of an important theorem from Serre and Deligne that in every modular form of weight 1 we can attach a linear representation. This representation is unique up to isomorphism.
[dvi] [ps] [pdf]

2004

Primes of the form x² + ny² (in English, 24 pages)
We study ring class fields of orders in imaginary quadratic fields to determine which primes are of the form x² + ny², where x, y integers, for arbitrary n. We give certain examples how our result works in practice.
[dvi] [ps] [pdf]

Optimal linear codes over GF(4) (in Greek, 18 pages)
A central problem in coding theory is that of finding the smallest length for which there exists a linear code of dimension k and minimum distance d, over a filed of q elements. We consider here the problem for quaternary codes (q = 4), solving the problem for k < 5 for all values of d.
[doc] [ps] [pdf]

2003

Primality test (Algorithms and Complexity) (in Greek, 26 pages)
We consider the primality problem, to decide whether a number is prime or composite. In this survey we show that PRIMES is in coNP and in NP. Then we try a probabilistic approach and we show that PRIMES is in coRP and in ZPP. Finally we present one of the most significant results of the last years: that PRIMES is in P.
Last update: Aug 31, 2005
[doc] [mdi] [pdf]

Smooth numbers and the quadratic sieve (in Greek, 12 pages)
With the help of Analytic Number Theory we consider the problem of optimizing the bound used in the quadratic sieve to factorise numbers.
[doc] [ps] [pdf]

The main linear coding theory problem (in Greek, 27 pages)
Central problem in coding theory is that of constructing optimal codes for a variable (length, dimension, minimum distance), over a field of q elements, while keeping the other two constant. Here we present one version of the problem, with the help of Finite Geometries, and all the known results until now.
Last update: Jan 14, 2004
[doc] [ps] [pdf]

2002

A lecture on Groebner bases (in Greek, 12 pages)
We study the methods of the Groebner bases in order to solve problems concerning polynomial ideals with algorithmic or computable methods.
[doc] [ps] [pdf] [html]

Conferences/Summer Schools

A list of conferences and summer schools I attended:

2018	13-15/10	Wikimedia CEE Meeting 2018	Lviv	Ukraine
2018	29-30/9	Sumer School on "Educational Technologies"	Corfu	Greece
2018	18-20/5	Wikimedia Hackathon 2018	Barcelona	Spain
2018	20-22/7	Wikimedia Conference 2018	Berlin	Germany
2018	8/3	WikiGap 2018	Nicosia	Cyprus
2017	4-5/11	Fosscomm 2017	Athens	Greece
2017	13-15/10	EEPEK	Larisa	Greece
2017	7/10	WikiFemHack	Thessaloniki	Greece
2017	22-25/9	Wikimedia CEE Meeting 2017	Warsaw	Poland
2017	19-21/5	Wikimedia Hackathon 2017	Vienna	Austria
2017	13-14/5	OSCAL '17	Tirana	Albania
2017	28-30/4	9th Conference on Education Technologies	Syros	Greece
2017	21-23/4	5th Pan-Hellenic Scientific Conference ETPE/ASPETE	Athens	Greece
2017	31/3-2/4	Wikimedia Conference	Berlin	Germany
2017	10/1	AtheCrypt 2017	Athens	Greece
2016	17/12	A Saturday for Hybrid Arts & Wikipedia	Athens	Greece
2016	5-6/11	Education at ICT days	Athens	Greece
2016	15/10	ThessHack – Wikimedia hackathon	Thessaloniki	Greece
2016	27/5	Wikimania 2016	Esino Lario	Italy
2016	22-24/4	Wikimedia Conference	Berlin	Germany
2016	1-3/4	Wikimedia Hackathon 2016	Jerusalem	Israel
2016	30/3	WikiArabia Tech Meetup 2016	Ramallah	Palestinian Territories
2015	7-8/5	Education at ICT days	Athens	Greece
2015	6-8/11	Fosscomm 2015	Athens	Greece
2015	23-25/10	EEPEK	Larisa	Greece
2015	9-11/10	CIE 2015	Pireaus	Greece
2015	10-13/9	Wikimedia CEE Meeting 2015	Voore	Estonia
2015	27/5	AgaTha 2015	Athens	Greece
2015	23-25/5	Wikimedia Hackathon	Lyon	France
2015	10/1	AtheCrypt 2015	Athens	Greece
2014	19-21/12	Wikimedia CEE Meeting 2014	Kiev	Ukraine
2014	10-12/10	CIE 2014	Corfu	Greece
2014	5-11/8	Wikimania 2014	London	U.K.
2014	7-8/6	Education and Road Safety	Corfu	Greece
2014	9-11/5	Wikimedia Hakathon	Zürich	Switzerland
2014	7/1	AtheCrypt 2014	Athens	Greece
2013	15-17/11	Anagnostakis-Patrikios-Sachtouris	Corfu	Greece
2013	7-11/8	Wikimania 2013	Hong-Kong	China
2013	26-30/5	Eurocrypt 2013	Athens	Greece
2013	24-26/5	Wikimedia Hackathon	Amsterdam	The Netherlands
2013	7/1	Athens Cryptographic Day	Athens	Greece
2012	12-14/7	Wikimania 2012	Washington D.C.	USA
2012	6/4	Cryptography and itsapplications in the Armed Forces	Vari	Greece
2011	4-7/8	Wikimania 2011	Haifa	Israel
2011	29/4	Intercity Number Theory Seminar	Rijksuniversiteit Groningen	The Netherlands
2010	18-19/11	North German Algebraic Geometry Seminar (NoGAGS)	Oldenburg	Germany
2010	18-22/10	Workshop on Elliptic Curve Computation (ECC 2010)	Microsoft Research in Redmond, WA	USA
2010	17-18/6	North German Algebraic Geometry Seminar (NoGAGS)	Hannover	Germany
2010	17-21/5	GTEM - Workshop on Computational Number Theory and Arithmetic Geometry	Leuven-Heverlee	Belgium
2009	19-20/11	North German Algebraic Geometry Seminar (NoGAGS)	Berlin	Germany
2009	13/11	Intercity Number Theory Seminar	Rijksuniversiteit Groningen	The Netherlands
2009	11-12/9	Workshop on Factoring Large Integers	Bochum	Germany
2009	24-26/8	13th Workshop on Elliptic Curve Cryptography (ECC 2009)	Calgary	Canada
2009	19-22/8	Summer school on Elliptic Curve Cryptography	Calgary	Canada
2009	9/7	Festkolloquium und Oberseminar zu Ehren von  Prof. Dr. Dr. h.c. Gerhard Frey	IEM, University of Duisburg-Essen, Essen	Germany
2009	8/5	Intercity Number Theory Seminar	Rijksuniversiteit Groningen	The Netherlands
2009	4-6/5	Workshop on Pairings in Arithmetic Geometry and Cryptography	IEM, University of Duisburg-Essen, Essen	Germany
2008	22-24/9	12th Workshop on Elliptic Curve Cryptography (ECC 2008)	Utrecht	The Netherlands
2008	27/7-5/8	German-Israel Minerva Summer School 2008: Arithmetic Geometry and Public Key Cryptography	Tel Aviv	Israel
2008	22-23/4	Workshop on Factoring Large Numbers, Discrete Logarithms and Cryptanalytical Hardware	IEM, University of Duisburg-Essen, Essen	Germany
2008	22-23/1	Workshop on Arithmetic Geometry	IEM, University of Duisburg-Essen, Essen	Germany
2007	5-7/9	11th Workshop on Elliptic Curve Cryptography (ECC 2007)	Dublin	Ireland
2007	3-4/9	Tutorial on Elliptic and Hyperelliptic Curve Cryptography 2007	Dublin	Ireland
2005	19-21/9	9th Workshop on Elliptic Curve Cryptography (ECC 2005)	Copenhagen	Denmark
2005	12-16/9	FICS-Summer School on "Elliptic Curves in Cryptography"	Copenhagen	Denmark
2005	23-29/7	Number Fields and Curves over Finite Fields	Anogia Academic Village, Crete	Greece
2005	30/5-3/6	Anogia Algorithmica '05	Anogia Academic Village, Crete	Greece
2004	20-22/9	8th Workshop on Elliptic Curve Cryptography (ECC 2004)	Bochum	Germany
2004	13-17/9	Summer School on "Elliptic Curves in Cryptography"	Bochum	Germany
2004	08-10/7	From Arithmetic to Cryptology, Conference on the occasion of Gerhard Frey's 60th birthday	University of Duisburg-Essen, Essen Campus	Germany
2003	18-25/2, 10-13/6	Lectures on Cryptography by G. Frey	University of Crete, Heraklion	Greece
2003	20-27/8	Lectures on Cryptography by R.A. Mollin	University of Crete, Heraklion	Greece
2002	15-27/7	Summer School in Mathematics 2002	Heraklion	Greece
2001	17-21/7	3rd Panhellenic Logic Symposium	Anogia Academic Village, Crete	Greece

Wikimania Takes Manhattan

 Wikimania Takes Manhattan was a special pre-Wikimania 2012 weekend in New York City, organized by Wikimedia NYC as a welcome for international visitors eager to experience the Big Apple and self-proclaimed "Capital of the World".

Activities took place from July 4th (Independence Day) to the morning of Monday July 9.