MAT5600 Spring 2013
Differential Geometry Class and HW Log
Here is a daily log of what we did in class and what you should do after
class. The day of the week is abbreviated for each class: MWF. There will be
14x3 = 42 classes. All links to Maple worksheets, paper handouts or the web URLs
used in class will appear here. [Sorry, no amusing
You Tube links.]
There is no required syllabus, no content that has to be covered at all costs
by the end of the semester. We are here to enjoy calculus and linear algebra in action and learn
something along the way about its power to describe one unifying aspect of our
world.
- M: January 14, 2013.
First Day in last minute classroom change: Mendel G87.
Read this:
Central ideas of calculus:
straightness and curves, zooming in to straighten out in order to quantify
rates of change, measuring curvature by changing linear zoom line.
In class:
Hands on play with the idea of curvature and parallel transport on a cone by
itself, then tangent to a sphere, then tangent to a planar circular orbit
around a central body deformed by the presence of that body (EEK!
wormholes! general
relativity already?!)
[pdf, printed at
115%,
paper handout in class, cut along positive x-axis to allow fold to a
cone of your choice by lining up the cut edge with a ray for polar angle
sliding from between say 7Pi/6 and 5Pi/3]
Discussion [polargrid.mw, terrible export from
Maple to pdf,
answers now included in Maple worksheet].
I meant it when I said we were going to have fun in this class, but can we
keep this up? [Everything is relative, no...? yuck, yuck]
Read the Preface and Chapter 0 of dr bob's
Differential Geometry book up to but not including the final Geometry
subsection unless you can' t stop yourself.
[Excerpt
file pages 1-19]
Make sure you have
Maple 16 on your laptop. It is easy to download and install. If you have
problems, ask bob for help.
We will revisit this
geodetic effect later on when we understand better the geometry. For now
it is just a motivator.
Will the dr bob show classroom automatic recording be useful or not?
Please send me an email (or reply to the email I sent you) sometime
this week telling me a bit about yourself, your previous math classes, your
previous experience with Maple if any, your comfort level with computers and
graphing calculators (we won't use the latter) and why you chose this
course.
- W: Return your filled out
schedule sheet from Monday's class [3
letter dorm abbreviations].
bob talks about Chapter 0. Finish reading Chapter 0 and try the problems at
the end.
Read Appendix A.1 on the hyperbolic functions. If
you have a calculus book, check out the section on hyperbolic functions
[Stewart: Section 3.11].
- F: bob discusses hyperbolic functions, pseudospherical coordinates in
plane and hyperbolic rotations in anaology with ordinary rotations based on
circles.
[hyperbolic-trigonometric.mw,
hyperbolicrotations.htm,
hypaddidentities.mw]
Begin reading Chapter 1: sections 1 and 2. Try some of the problems. These
also review solving linear systems and the eigenvalue problem in our
notation, but not a problem if you have not done this before. It is not
essential to our applications.
WEEK 2:
M: 1/21: MLK day, no class. Class info
sheet. Read this.
- W: I am trying to find a way to complement the reading by presenting
some material in class, while discussing questions about the reading.
Today I look at Exercises 1.2.1-3 to illustrate some things about vector
spaces and how we get interesting structures on them [ 3:
asymmatrices-crossprod.mw,
quadratics.mw].
I have no one to proof my book edits, so glitches occur like in Exercise
1.2.2 where I forgot to put the usual quadratic function representation
Q(x) = a x2 +b x +c at the beginning
of the problem.
The subsections on solving linear systems and eigenvectors summarize
material from MAT2705 but are a bit heavy and we don't need them at so
serious a level: we will solve linear systems with Maple when we need them
and they will usually have a unique solution using matrix inverses, and eigenvectors are just a
nice example for us but not crucial.
Read Section 1.3 on linear functions. Try some problems.
Today we saw through 3 examples that 3 different vector spaces whose elements
("vectors") are polynomials or matrices, once we introduced an obvious basis, put us into
an Rn space, so essentially every n-dimensional vector space is
like one of those simple spaces once we introduce a basis and express the
coordinate vector or component vector of the abstract vectors in the space,
whatever their mathematical origin. We will build all of our structure on a
vector space V, and its space of linear functions, the dual space. These
lead to vectors and covectors with a natural pairing to produce scalar
invariants (the value of a linear function on a vector). Index notation
helps us distinguish these two basic spaces with upper and lower indices,
from which we built more complicated objects (multilinear functions on
vectors = tensors). Much of the structure we use already in multivariable
calculus will then be put into context in this new light: dot product, cross
product, determinant, matrices and inverses, linear transformations like
rotations,etc. This is a slow process so we need patience to get it right,
rather than just rushing to the action (exciting geometry).
- F: bob tries to reprocess 1.3 orally and visually. Read Section 1.4
on linear transformations as tensors, do the 4 exercises.
WEEK 3[-1]:
- M: 1/28: bob presents 1.4. discusses exercises. Read Section 1.5. Try
the exercises.
- W: 1/30: bob presents 1.5. discusses exercises.
Begin reading Section
1.6 up to a "Geometric interpretation of index shifting" (page 93). Try
some of the exercises, your choice.
- F:
2/1: class roster handout;
1/30: bob presents 1.6;
notes online;
questions and answers? Monday?;
Finish section 1.6, "Cute fact" section not essential but fun. There
are a number of interesting problems for the weekend.
We definitely will talk about these Monday.
Read Appendix A.2 on special relativity. [Note we have to wait to do
Exercise 1.6.5 till after we cover Appendix A.3.]
WEEK 4[-1]:
- M: 2/4: Bring laptops to class; recall
Maple file list; for example, the
4x4 matrix multiplication requires Maple:
electromagnetic field tensor matrix;
Read 1.7. Try problems. More specific Tuesday.
- W: 2/6 bob presents 1.7 key ideas (yes, it is heavy, but it is a tour of
important ideas that we cannot pursue except for the central ones);
example of exponential and eigenvector diagonalization
matrixexponential2by2.mw
;
[Maple matrix examples
rotationmatrices.mw
(1.7.11 spin calculations done a bit clumsily),
asymmatrices-crossprod.mw,
GLplusT.mw Exercise
1.7.3, for more see list]
Read 2.1-3.
- F: 2/8: bob presents 2.1-3, 4.1-2. key ideas. Finish reading Chapter 2.
We don't need multivariable Taylor series (last section), but it is worth
being exposed to. Don't worry about related exercises unless you are
interested.
Note: multitaylor.mw,
momentsofinertia.mw,
which show how one can use Maple to evaluate easily these kinds of
calculations.
WEEK 5[-1]:
- M: 2/11: bob presents 4.3, part 1: key ideas. Read Chapter 3 Review of what we have done so far. Easy!
Read 4.1 (easy: chatter about determinants) and 4.2: the wedge product. Do
4.2 problems.
- W: 2/13: Read 4.3 up to but not including the subsection "The metric dual." Do at least Exercise 4.3.3,
4.3.5, 4.3.6 which are
more indicative of how we will actually use the dual. The abstract index
stuff is not essential if you believe the results. See Appendix C, problem
solutions for a few examples (so far, only a few).
- F: 2/15: Continue reading rest of 4.3, then 4.4 which summarizes what
you already read with an explicit example, then 4.5 but this is just for
culture (but lots of interesting points to go off on a tangent for physics
applications). Meanwhile bob will think about Appendix A.3 for reminding
ourselves about multivariable vector calculus of curves in space. The plan
is Appendix A.4 next, then Part 2. We basically have the foundation we need
now, the rest of Chapter 4 after the unit n-vector/covector is icing on the
cake.
Appendix A.3 curves in space review:
geometry of space curves curvature and acceleration;
[example Maple worksheets:
osculating_circle_cubic.mw,
osculating_circle_helix.mw]
helixTNB.mw,
helix-lorentz.mw
(comparing the Euclidean and Lorentz helices)
>
with(Student[VectorCalculus]):
SpaceCurveTutor(<t,t2,0>,t=-1..1) from the Tools Menu, Tutors, Vector Calculus,
Space Curves [choose
animate osculating circles]
WEEK 6[-1]:
- M: 2/18: Read Appendices A.3, A.4 multivariable calculus review
of curves and surfaces.
bob talks about A.3.
- W: 2/20: bob talks about A.4 and contrasts surface area of hyperboloid in Euclidean/Minkowski geometry of
3-space [hyperboloidsurfacearea-e3-m3.mw].
Part 2! Chapter 5. Calculus.
Read? I am confused about what I said to do, problems with web edit
interface!
- F: 2/22: bob covers 5.1-2.
Read 5.1-2. Do some problems. These are pretty routine.
WEEK 7[-1]:
- M: 2/25: Read 5.3-4. Do problems that are not repetitive of earlier ones.
See especially Maple worksheet
rotationmatrixeigenvectors.mw for eigenvector analysis of a rotation for
the corresponding Exercise. the key idea is how vector fields as first order
derivative operators really are fundamental.
Tempting look forward
Added Monday night: problem 5.3.6 on the
equiangular =
logarithmic spiral curve vector field in polar coordinates. Added
Tuesday new Problem part 5.3.5.c).
- W: 2/27: Read 5.5-5.7 on polar and cylindrical, spherical coordinates,
and cylindrical coordinate frame calculations. Try some exercises (not all).
bob introduces polar coordinate calculations, then talks about projections
and using an orthonormal frame to project vectors making an orthogonal
direct sum of the vector space.
- F: 2/29: Read 5.8-9. on spherical coordinate frame calculations. Try some
exercises. bob introduces spherical coordinate frame and its
derivatives (6.1 covariant derivatives, read if you have time). [see last
section of
rotationgroup-eulerangles.mw]
Spring Break.
enjoy and be safe.
[Don't work too hard.]
Week 8[-1]:
- M: 3/11: Read 6.1-6.4. Don't worry about details reading 6.1, this is
just an example of old fashioned tensor calculus, but the idea of how
special Cartesian coordinates are is useful. 6.2 is easy. [See
rotationgroup-eulerangles.mw]. 6.3 deals with matrix group properties. 6.4 is
short and simple, some practice. Try some of the problems, most are
computationally straightforward.
bob goes on about covariant derivatives, independent of particular constant
metric.
- W: 3/13: Read 6.5-6.6. Try some problems. Using compatibility with metric to evaluate connection
components. Maple:
tensortemplate.mw,
rotationgroup-eulerangles.mw.
- F: 3/15: Review day. Come armed with problems/concepts you want to have
discussed.
Read 6.7-6.8. [6.9 is optional if you are interested in rigid body
motion.]
WEEK 9 [-1]:
- M: 3/18: Read 7.1-7.2 [then 7.3-7.4 which are repetitive of what
we have already covered, I should edit them...]. The exercises 7.1-7.2 are more
straightforward evaluations for the
most part.
For fun I added a problem on the angular momentum ladder operators and a
followup remark on the gluon strong interaction SU(3) Lie algebra matrices
at the end of section 6.8, not for you to do necessarily but to show you how
close we are to being able to understand much more that you might have
dreamed of... We will return to this in chapter 11 differential forms.
I also added an exercise (in the same spirit) at the end of Chapter 4 on the
quaternions, for those of you who might have encountered these fascinating
mathematical objects at some point in your lives. It is exactly the
SU(2)-SO(3,R) connection brought out in a previous exercise just before it.
- W: 3/20: bob talks about 7.1-7.2.
Parallel transport finally arrives! Read 8.1.
- F: 3/22: bob talks about 8.1-8.2 parallel transport [sphere with
hair: rotationgroup-eulerangles.mw].
Read 8.2-8.3.
WEEK 10 :
http://www34.homepage.villanova.edu/robert.jantzen/notes/torus/2011-11-talk/2011-11-18.htm
[on geodesics, gravitational orbits]
[fun
video (NYTimes) from
bob's talk on GR,
geodesics and pasta]
[see surfaces of
revolution worksheet (the animation is in the monster worksheet
torus_geodesics.mw, we will get to that soon enough)]
- M: 3/25: 8.3-8.4 geodesics! and surfaces of revolution. Read 8.4.
[check last part added to 8.3]
- W: 3/27: bob talks about 8.4. [If you read 8.4 before 4:20pm Tuesday,
read it again, since bob finished major editing then including improving the
black hole precession calculation and the plots that illustrate it.]
Read 8.5-8.6 or just catch up. I will talk about these when you return.
Easter Break.
WEEK 10 continued:
- W: 4/3: bob talks about 8.5. Read 8.5, then without worrying
about details or exercises unless one appeals to you read 8.6-8.7
- F: 4/5: Maple showtime day. bob plays with the
torus numerical geodesic worksheet
template. discussed Maple integration problems that need human guidance
in the spherical geodesic worksheet [see Maple for chapter 8].
WEEK 11:
- M: 4/8: Read 8.9 and do the problems. bob talks about 8.9. [you
can read about torus geodesics 8.8 and corkscrew pasta geodesics 8.11 in
more detail from the PDF articles here].
- W: 4/10: Read 8.4, 8.12 on black hole 3-geometry of equatorial plane, where
orbits = geos take place. in progress. finish schwarzschild connection
1-form evaluation, then look at answer in notes.
[spherical pendulum problem origin:
http://www34.homepage.villanova.edu/robert.jantzen/gem/centalk.htm]
- F: 4/12: bob jumps to intrinsic curvature. Read 9.1. We will return to
the interesting geometries of chapter 8 once we have intrinsic and extrinsic
curvature tools.
[connection and curvature working in a frame with Maple:
blackholetensorcalcs.mw]
WEEK 12:
- M: 4/15:
Euler's 306th birthday;
interpretation of curvature in terms of parallel transport around a
shrinking loop in a plane. Read 9.2-9.3.
- W: 4/17: Read 9.4. We now have lots of interesting surfaces to
play with and many suggested exercises [see also
Tori,
Cavatappo 1.0,
Cavatappo 2.0,
Lorentz Cavatappo] that you might take into consideration for a short
presentation on final exam day as you requested. Once we finish extrinsic
curvature next week, you will have the final tool to understand these
geometries.
- F: 4/19: Read 10.1. bob stalls out, like his car this morning.
bob will ramble about using Maple for geos. Field questions if you guys can
come up with any. Go over some problems. [Gauge theory "light" reading for
15 bucks used at
Amazon, read reviews]
WEEK 13:
- M: 4/22: bob presents 10.1.
- W: 4/24: bob presents 10.4. Read 10.2-10.4. [optional 10.5]. There are
many interesting geometries (look back also at chapter 9 geometries),
problems: intrinsic geometry (geodesics), extrinsic geometry (normal
behavior, eigenvector analysis of shape tensor). I will move on to chapter
11, differential forms.
- F: 4/26: bob presents 11.1-4. Read these sections. Try some
problems to recall integration from multivariable calculus.
WEEK 14:
- M: 4/29: bob presents 11.5-11.6. Read these sections.
- T(F): 4/30: bob presents 11.7-11.8 (+11.9-11.10). This is it. Was I too
ambitious? Have you gotten something positive to take away from this course?
- W: 5/01: CATS forms. Final remarks on adjoint matrices and adjoint
codifferential relation to exterior derivative and Maxwell's equations.
Friday, May 10: 8:30-11:00. final exam slot for
short low key
presentations on any topic you choose. email me about it if you cannot stop
by in person?
No in class exams, no mandatory HW. At end of semester I would like to see
a collection of the problems you have done to show your engagement in the
course, and some supporting work for your short presentation on the exam day.
dr bob jantzen villanova university
14-may-2013