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Currently,
I am an Associate Professor in the Department of Physics and Astronomy
and an Adjunct Professor in the Department
of Mathematics at the University of Manitoba.
I am the Director Elect of the Winnipeg Institute for
Theoretical Physics and an associate at the Center for Advanced Mathematical Sciences
at the American University of Beirut.
I.
Books
II.
Papers
III.
Papers in Preparation
28.
B*-algebras
of operators and study of positive operators on a free Banach
space of countable type over the complex Levi-Civita
field, Jose Aguayo, Miguel Nova and Khodr Shamseddine, to be submitted
soon.
Contributed
Talks at Conferences
Invited
Talks, Seminars and Colloquia at Universities
My research interests and
activities include various areas of non-Archimedean Analysis: power series and analytic
functions, measure theory and integration, optimization, existence and
uniqueness of solutions of differential equations, complex analysis,
multivariable analysis and functional analysis. The focus of my research has
been on the Levi-Civita fields which were first
introduced by the Italian mathematician Tullio Levi-Civita at the end of the nineteenth century. Of those Levi-Civita fields, one (which we denote by R) is of particular interest; it is shown to be the smallest
non-Archimedean field extension of the real numbers that is complete in the
order topology and real closed. In fact, R is small enough so that the numbers
of the field can be implemented on a computer; and this allows for many useful
applications, one of which is the fast and accurate computation of the
derivatives of real-valued functions up to high orders.
We studied two topologies
on R: the valuation topology induced by the order
on the field, and another weaker topology induced by a family of semi-norms,
which we call weak topology. We showed that each of the two topologies results
from a metric on R, that the valuation topology is not
a vector topology while the weak topology is, and that R is complete in the valuation topology while it is not in the weak
topology. Then we studied the properties of both topologies in detail; in
particular, we gave simple characterizations of open, closed, and compact sets
in both topologies. Finally, we showed that the metric which induces the weak
topology is translation invariant.
We studied convergence of
sequences and series in both topologies mentioned above, which led to an
exhaustive study of power series. A handful of people had investigated power
series on the Levi-Civita fields before, but all the
previous studies had been restricted to the special case of power series with
real coefficients. We have dropped that restriction and showed that power
series on Levi-Civita fields have all the nice
smoothness properties that real power series have. In particular, they satisfy
the intermediate value theorem, the extreme value theorem, the mean value
theorem and the inverse function theorem; they are infinitely often
differentiable; and they are re-expandable around any point within their domain
of convergence.
While it is a known fact
that conventional continuity or differentiability are not sufficient to
guarantee that a function on a closed interval of a non-Archimedean field be
bounded or satisfy any of the common theorems of real calculus, we have shown
that under mild conditions, differentiability is sufficient for the function to
assume all intermediate values and a differentiable inverse function. We also
showed that conventional differentiability is not the right one to study
optimization questions on non-Archimedean fields in general; and based on a
stronger concept of differentiability, we studied finite-dimensional
optimization both with and without constraints. In both cases, we derived
necessary and sufficient conditions of first and second order for a function to
have a local minimum at a point of its domain.
We developed a measure
theory and integration on the Levi-Civita field R. We introduced a measure that proved to be a natural generalization of
the Lebesgue measure on the field of the real numbers
and have similar properties. Then we introduced a family of simple functions
from which we obtained a larger family of measurable functions and derived a
simple characterization of such functions. We studied the properties of
measurable functions, we showed how to integrate them over measurable sets, and
we showed that the resulting integral satisfies similar properties to those of
the Lebesgue integral of Real Analysis.
Most recently, together with my
collaborators Jose Aguayo and Miguel Nova from
Concepcion (Chile), we developed an operator theory on a Banach
space over C:=R+iR. Let c_0 denote the space of all
null sequences of elements of C.
The natural inner product on c_0 induces the sup-norm of c_0. We showed that
c_0 is not orthomodular; then we characterized those
closed subspaces of c_0 with an orthonormal complement with respect to the
inner product. Such a subspace, together with its orthonormal complement,
defines a special kind of projection, the so-called normal projection. We
presented a characterization of such normal projections as well as a
characterization of other kinds of operators, the self-adjoint
and compact operators on c_0. Then we worked on some B*-algebras of operators,
including those mentioned above; we studied normal and Hilbert-Schmidt
operators; and finally, we studied the properties of positive operators, which
we then used to introduce a partial order on the B*-algebra of compact and
self-adjoint operators on c_0 and studied the
properties of that partial order.
Building on my previous
research, I am establishing a research program in Non-Archimedean Analysis at
the University of Manitoba. The long term aim of my research program is to
develop a complete analysis which holds for any real closed Cauchy-complete
non-Archimedean field extension F of the field of real numbers R whose skeleton
group is Archimedean. The theorem of Hahn entails that any such field F is
isomorphic to a subfield of a field of generalized power series with
coefficients in R and exponents forming a well-ordered subset of some ordered abelian group G. As a part of my
research program, I have designed several research projects, any one of which
(or, in some cases, a combination thereof) could also be a suitable topic for
an interested student's M.Sc. or Ph.D. thesis.
Training of Highly Qualified Personnel (at
U of M)
I.
Graduate Students
1.
William
Grafton (September 2013- ); M.Sc. candidate (Mathematics).
2.
Angel
Barria (January 2013- ); PhD candidate (Mathematics).
3.
Darren
Flynn (July 2012- ); M.Sc. candidate (Physics).
4.
Andrew
Senchuk (January 2010- ; I am co-advisor, with
advisor: Prof. Gerald Gwinner); PhD candidate (Physics).
II.
Undergraduate Students
o
Summer
Students
1.
Gidon Bookatz (2013);
NSERC-USRA student in the joint Math-Physics Honours
program.
2.
William
Grafton (2012); undergraduate summer student in the joint Math-Physics Honours program. William will start his M.Sc. in
Mathematics under my supervision in September, 2013.
3.
James
Roberts (2011); undergraduate summer Honours student,
Department of Physics at the University of Winnipeg.
4.
William
Grafton (2011).
5.
Todd
Sierens (2010); undergraduate summer student in the joint Math-Physics Honours program; currently a PhD student at the University
of Waterloo and the Perimeter Institute.
6.
Todd
Sierens (2009); NSERC-USRA student in the joint Math-Physics Honours program.
7.
Trevor
Rempel (2009); NSERC-USRA student in the joint Math-Physics Honours
program; currently a PhD student at the University of Waterloo and the
Perimeter Institute.
o
Undergraduate
Honour Thesis:
8.
Cheng
Tang (2012-2013).
I.
At the University of Manitoba (May
2008- present)
o
Summer
2013: MATH 8430, Non-Archimedean Operator Theory (a reading course)
I.
At the University of Manitoba (May
2008- present)
a.
Graduate Students Advisory
Committees
i.
May 2011- present: Mark McCrea; PhD in Physics.
b.
Thesis Internal Examiner
i.
2010:
Bryan Penfound; M.Sc. in Mathematics.
ii.
2010:
Chandra Podder; PhD in Mathematics.
iii.
2010:
Mohammad Safi; PhD in Mathematics.
c.
Departmental Committees
i.
2012-2013:
1. Honours/Majors
Committee (Chair)
2. Curriculum Committee (Chair)
3. Term Work Appeals
ii.
2011-2012:
1. Honours/Majors
Committee (Chair)
2. Curriculum Committee (Chair)
iii.
2010-2011:
1. Honours/Majors
Committee (Chair)
2. Curriculum Committee
iv.
2009-2010:
1. Honours/Majors
Committee (Chair)
2. Curriculum Committee
v.
2008-2009:
Curriculum Committee
d.
Faculty of Science Committees
i.
2012-2013:
1. Director Elect of the Winnipeg
Institute for Theoretical Physics
2. Committee on Courses and
Programs (COCAP)
3. The Local Discipline Committee
ii.
2011-2012:
1. Committee on Courses and
Programs (COCAP)
2. The Local Discipline Committee
iii.
2010-2011:
The Local Discipline Committee
iv.
2009-2010:
The Local Discipline Committee
v.
2008-2009:
The Local Discipline Committee
e.
International Committees and
Professional Service
i.
Member
of the Scientific Committee for the 13th International Conference on
p-Adic Functional Analysis (to be held at University
of Paderborn, Germany, August 2014).
ii.
Member
of the Scientific Committee for NUMTA2013: Numerical Computations: Theory and
Algorithms (Falerna, Italy, June 17-23, 2013)
iii.
Organizer and chair of the Scientific Committee for the 12th
International Conference on p-Adic Functional
Analysis (University of Manitoba, July 2-6, 2012)
iv.
Member
of the Scientific Committee for the 11th International Conference on
p-Adic Functional Analysis (Universite
Blaise Pascal, France, July 5-9, 2010)
v.
Co-organizer
and member of the Scientific Committee for the 10th International
Conference on p-Adic and Non-Archimedean Analysis
(Michigan State University, USA, June 30-July 3, 2008)
vi.
Reviewer
for Zantrablatt Math (13 papers since 2009)
vii.
Referee
of several papers for Math journals (6 papers since 2008.)
viii.
Referee of 4 research proposals (3 for Qatar
Foundation and 1 for the Austrian Science Fund.)
f.
Community Service: Member of the Board of Directors for
Campus Daycare since May 2011.
g.
Outreach: Volunteered at info days every year
(2009-2013).
II.
At Western Illinois University
(August 2003- May 2008)
a.
Graduate Students Advisory
Committees
i.
2003-2004: Javid Siddique;
M.Sc. in Mathematics.
ii.
2003-2004: Duygu Inceoz;
M.Sc. in Mathematics.
b.
Thesis External Examiner
i.
2008: Dodzi Attimu;
PhD in Mathematics; Howard University (US).
c.
Departmental Committees
i.
2007-2008
1. Graduate Committee (Chair)
2. Personnel Committee
3. Curriculum Committee
ii.
2006-2007
1. Graduate Committee (Chair)
2. Colloquium Committee
3. Computer Affairs Committee
4. Curriculum Committee
iii.
2005-2006
1.
Graduate Committee (Chair)
2.
Colloquium Committee
3.
Curriculum Committee
iv.
2004-2005
1. Graduate Committee (Chair)
2.
Colloquium Committee
3.
Curriculum Committee
4. Upper Division Curriculum Committee
v.
2003-2004
1. High School Relations Committee
2. Library Committee (Chair)
3. Upper Division Curriculum Committee
As the Chair of the Graduate Committee (Fall 2004-Spring 2008), I led the efforts of that committee in recruiting and advising graduate students as well as assisting the Department Chair with various matters pertaining to the graduate program. I have led the efforts of the Graduate Committee in preparing the proposals for revisions in the graduate program including new structure, courses and tracks to better serve the needs of the incoming graduate students. I gathered ideas, thoughts and suggestions from the various groups in the Department about the structure and the contents of the courses in the revised program and designed a web page for that purpose to facilitate the discussions and the exchange of ideas in the Department. As a result, proposals for a revised program were submitted and approved by the Dean and the Graduate Council; and the revised program started in Fall 2006.
d.
College (Arts and Science) and
University Committees
i.
2007-2008
1. University Research Council
2. Evidence of English Proficiency and Minimum TOEFL Requirements Committee
3. College of Arts & Sciences Graduate Studies Committee
ii.
2006-2007
1. University Research Council
2. Evidence of English Proficiency and Minimum TOEFL Requirements Committee
3. College of Arts & Sciences Graduate Studies Committee
iii.
2005-2006
1.
College of Arts & Sciences Graduate
Studies Committee
III.
At Michigan State University: Coordinator of the Math Learning Center (2002-2003), supervising
all the tutors and teaching assistants who worked at the center.
Maintained
by K. Shamseddine (last updated May 13, 2013). Top of home page.