Newspaper (El Pais, Spain) articles August 28, 1988 and March 19, 1989.

Papers starting 1985

Papers starting 1995

Papers starting 2005

Papers starting 2015

Papers starting 2020

Research seminar series at Portland State University (2005, 2006, 2010, 2011)

Research seminar series at Rockefeller University (1996, 1997, 2008, 2009)

A language page.

RESEARCH:

I have designed two new courses that I am very
excited to teach. Please, ask me about this material.

NUMBER THEORY:
I am writing an ambitious set of notes covering an introduction to several areas of number
theory. Here is the flyer for the full year course. It is designed to emphasize connections
with other areas of mathematics such as analysis, algebra and complex analysis, as well
as to make some classical results accessible to a wider audience of non-specialists.
The book "Numbers from All Angles" is based on a thoroughly corrected and rewritten
version of these notes, and will be published by Springer Nature.

DIRECTED NETWORKS:
In the summer of 2019, I participated in a summer school in Italy where I gave a mini-course
on the theory of directed graphs.  This resulted in the design of the 1 or 2 trimester course
"Directed Networks". Here is the flyer for the course. Some of the material has been worked
into slides: see part 1, part 2, part 3, and part 4.

NOTE:
All this material is "work in progress"; expect errors and other shortcomings.
I appreciate if you report errors and welcome constructive criticism.
You can find my email at the top of this page.

COMPLEX SYSTEMS:

I am the Director of the Complex Systems unit at PSU. My intent is to promote and help strongly
interdisciplinary practices in research and teaching. If you are interested in Complex Systems
(COSYS) as faculty, instructor, or student, or any other way, please, feel free to  contact me at the
above email.

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IMPORTANT 1: All answers on home works and exams must be justified,  even if  that is not evident from
                              the phrasing of the question. Answers without justification will receive partial credit at best.
IMPORTANT 2: Before turning in exams or HW's, write your first plus last name in the top right corner
                              of each sheet you turn in (even if you staple them together)!
IMPORTANT 3: While I actively encourage collaboration among students and may assign
                              take home exams on which you are allowed to collaborate:
                                    you must write your own exam yourself in your own words !!!
                              Copying, or even using something else as a template for your answers, is plagiarism
                              and will receive no credit whatsoever.
IMPORTANT 4: Homeworks are due on the day for which they are assigned,
                             at the beginning of class, and on paper.
                             Homeworks more than 10 minutes late will not be accepted, unless for valid reason
                             (medical must be accompanied by doctor's attest).

===============================================================================
FALL 2024:    MTH 256: Ordinary Differential Equations:

You can find the syllabus here. We meet in Univ Pointe 207 from 16.40 to 18.30 on Monday and Wednesday.
Office hours will be 18.30 to 19.00 on Mon and Wedn or by appointment.

GRADING KEY: Homework 20%, in-class perf. 20%, two in-person tests (including the final), each 30%.

MIDTERMS AND FINAL: No Telephones. No Calculator or Computer. No Notes. No Book.
                                          Pen and White Paper Only.
                                         Test1: Wednesday, Nov 06, in-class.
                                         Test2 (final): Monday, Dec 09, 17.30-19.20 in-class.

HOME WORK DUE:
          Mon,  Oct 07: Section 1.1: 4, 6-10, 13-15, 21-22. Section 1.2: 4, 26, 28, 30, 32, 34, 43.
                                Section 1.3: 6, 8, 10, 16, 22.
          Mon, Oct 14: 1.4: 1, 2, 5, 6. 1.5: 5-8, 11-14. 1.6: 5, 7, 8, 10, 30, 32, 34, 36, 40, 44.
                               1.7: 2, 4, 5, 8, 10, 13, 14.
          Mon, Oct 21: 1.8: 2, 4, 6, 8, 10, 12, 17, 18, 20, 32. 1.9: 2, 4, 6, 8, 10, 12, 21, 22.
          Mon, Oct 28: 2.1: 7, 8, 20, 22. 2.2: 7, 8, 9, 10, 19, 20. 2.3: 2, 4, 6, 8. 2.4: 2, 4, 5, 6, 7, 8, 9.
          Mon, Nov 04: 2.5: 1, 2. 2.6: 1, 3, 4, 8, 10. 2.7: 1, 3, 4, 5, 6.
          Wed, Nov 13: 3.1: 6, 7, 8, 16, 18, 24, 26, 28, 34. 3.2: 2, 4, 6, 8, 10, 12, 14. 3.3: 2, 4, 6, 8,
                               10, 12, 14.
          Mon, Nov 18: 3.4: 2, 4, 6, 8, 10, 12. 3.5: 6, 8, 9, 10, 12, 18, 22. (Section 3.5 can be turned in later.)
          Mon, Nov 25: 3.6: 2, 4, 6, 8, 10, 12, 14, 16. 3.7: 2, 4, 6, 8, 10, 12. 4.1: 2, 4, 6, 8, 10, 12.
          Mon, Dec 02: 4.2: 2, 4, 6, 8, 10, 12, 14. 4.3: 2, 4, 6, 8, 10, 12, 14.
          Bonus: Mon Dec 09: 4.4: 2, 4, 6, 8. 6.1: 2, 4, 6, 8, 10. 6.2: 2, 4, 6, 8, 10. 6.3: 2, 4, 12, 16.
                                            5.3: 1-8.

===============================================================================
WINTER 2025:    SYSC 410-510: Complex Systems:

You can find the syllabus here. 

GRADING KEY:

MIDTERMS AND FINAL:

======================================================================================

In most of my classes you will be either strongly encouraged, or even obliged
(graduate students) to turn in your HW in *.pdf format based on LATEX.
Here is a website where LATEX is explained: 
http://www.ctan.org/tex-archive/info/Math_into_LaTeX-4/