I am currently the Graduate Chair for the Department of Mathematics.
My lecture notes for Math 1600.
My papers, preprints and talks.
I am a Managing Editor of Homology, Homotopy and Applications.
Here are some photos from trips I have been on; I also have a Google+ page.
Contact information is below.
Research 
My research interests include algebraic topology
(especially stable homotopy theory and model categories),
derived categories,
modular representation theory,
mathematical physics (quantum gravity),
algebraic and scientific computation,
and category theory (especially higher categories).
Research groupDan Christensen (faculty)Martin Frankland (postdoc, 20132015) Chris Kapulkin (postdoc, 20142016) Gaohong Wang (M.Sc. 2010; Ph.D. student, Sept 2010 to August 2014; postdoc Sept 2014 until present) Brendon Phillips (M.Sc. student, Sept 2014 to August 2015) Rui Dong (M.Sc. student, Sept 2014 to August 2015) 
What's this? 
I intend to accept several new graduate students in the areas of homotopy theory, topology, representation theory, mathematical physics, etc. If you are interested, please contact me and send an application to our department mentioning my name. To be sure your application can be evaluated fully, please have at least three people submit detailed letters of reference, and also include information about the contents of the courses you have taken.
I encourage eligible people in topology or physics to apply for an NSERC Postdoctoral Fellowship, an NSERC Banting Postdoctoral Fellowship (domestic and international applicants eligible), any other NSERC postdoc, an NSF PDF (e.g. a International Research Fellowship Program postdoc, or a Mathematical Sciences Postdoctoral Research Fellowships or a Distinguished International Postdoctoral Research Fellowship), or similar to be held at Western.
The Canadian Government has many scholarships and fellowships that are available for people from many different countries.
Recent Teaching 
Fall 2014  Linear Algebra I, Math 1600a. 
Summer 2014  Representation Theory, Math 9140a. 
Winter 2014  Linear Algebra I, Math 1600b. 
Fall 2013  Linear Algebra I, Math 1600a. 
Algebraic Topology, Math 4152a/9052a. 
Other 
The Hopf archive
of research papers in topology.
The Front for the xxx Mathematics
Archive. Direct to the xxx archive.
The Ktheory archive.
MathSciNet, which contains
searchable reviews of almost all mathematics publications and many
physics publications as well.
SAGE is a wonderful program which interfaces to Magma, Maple, Mathematica and MATLAB, and the free programs Axiom, GAP, GP/PARI, Macaulay2, Maxima, Octave, and Singular. It is freely available and open source. Dave Rusin's Mathematics Essays, and his article about algebraic topology. If you find math fun, consider becoming a math major. Talk to me or anyone else in the department if you're curious. A java calculator that performs exact computation with the constructable reals, using a java library. The Rainbow Cinemas at the Galleria. Some thoughts on investment strategies. 

Contact information 
Dan Christensen
Department of Mathematics
The University of Western Ontario
London, Ontario N6A 5B7
Canada
Office phone: (519) 6612111 x86530
Fax: (519) 6613610 (include my full name)