Dr. Sarah's Math 4710/5710 Web Page - Fall 2003

  • Dr. Sarah's Office Hours
  • To access WebCT
    Direct WebCT Access if Campus Pipeline is Down
  • Class Highlights-Day by Day
  • Syllabus and Grading Policies
  • DUE/REVISION Dates

    Date

        WORK DUE at the beginning of class or lab unless otherwise noted! Be sure to follow the Proof-Writing Samples and the Proof-Writing Checklist
     
    Dec 16 - Tues
    • Final Project Presentations 3-5:30pm
    • Topology of the Universe by Fabien Dass
    • Euler's Formula and Topological Invariants by Tiffney Duke
    • Algebraic Topology by John Foley
    • Topology of the Internet by Lindsay Lamb
    • Knots by Natahsa Mabe
    • Topology and Economics by Ryan Nichols
    • Topology and Electric Circuit Design by Jonathan Watson

    Fri - Dec 12
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    Dec 9 - Tues
    • PS 9 due at 5pm
      For each of the following, if the set is not compact, then produce an open cover that has no finite subcover. Otherwise, prove that it is compact: [0,1), {1/n s.t. n is a natural number}, [0,infinity), X with the cofinite topology.
      p. 131 number 11
      Prove that the finite union of two compact sets in a space X is compact in X.
      Extra Credit Show that the intersection of two compact sets in a Hausdorff space X is compact in X.
      Extra Credit Show that Hausdorff is required in the above statement, ie that the intersection of compact subspaces of a space X is not necessarily compact as follows:
            Look at Y=[0,1] U [2,3] with the equivalence relation ~ on Y s.t.    t ~ t for all t,    t ~ t+2 for all t in [0,1),    t ~ t-2 for all t in [2,3)
            Show that Y/~ is not Hausdorff
            Show that [0,1] U [2,3) is compact in Y/~
            Show that [0,1) U[2,3] is compact in Y/~
            Show that the intersection of these two compact sets in Y/~ is not compact in Y/~
      Extra Credit Prove that If X is compact Hausdorff under both T and T', then T=T' or they are not comparable.

    Dec 2 - Tues
    • PS 8
      Using ideas of connected spaces, show that no pair of the following is homeomorphic:   (0,1),   (0,1],   [0,1]
      Using ideas of connected spaces, show that   R^2 and R   are not homeomorphic
      Show why each of the following is or is not connected:   R_l and R_zar=R_fc

    Nov 25 - Tues
    Nov 20 - Thur
    • Problem Set 7 is due by 5pm (Hints will be posted on WebCT)
      2.6       1, 9, 17b.
      (Grad) just the closed part of 5

    Nov 18 - Tues
    • Go over Problem Set 6 Solutions and take WebCT quiz 4 (open notes).

    Nov 13 - Thur
    • Test up to and including Hausdorff

    Nov 11 - Tues
    • Problem Set 6 due by 5pm
      Prove that X is discrete iff every function f : X-->R is continuous
      p. 57 #20
      Prove or Disprove that the following are homeomorphic
      a) S^1 and {(x,y) | max(|x|,|y|) = 1}, both with the subspace topologies of R^2.
      b) R with the standard topology and R_cf with the finite complement topology.
      c) (Extra Credit) [1,2) and {0}U(1,2) with the subspace topologies of R.

    Nov 6 - Thur
    • Skim 1.7, 2.1 and 2.2
    • Work on PS 6

    Nov 4 - Tues
    • Self-Evaluation for oral test due. Reflect on your oral presentations. What are aspects of your presentations that went especially well? How about aspects that could use improvement? Give yourself a grade.
    • Work on PS 6

    Oct 30 - Thur
    • Go over PS 5 Solutions and compare them with your work. Then take WebCT quiz 3.

    Oct 28 - Tues
    • Test 2 on examples and definitions up through and including Problem Set 4. Oral test continued. Be able to answer your questions and also be able to recite any related definitions. Both are closed to notes.

    Oct 21 - Tues
    • Problem Set 5
      Which of the following are Hausdorff? (Informally justify your answers.)
            a) X={1,2,3} with the topology={Empty set, {1,2}, {2},{2,3},{1,2,3}}
            b) The discrete topology on R
            c) The Cantor Set with the subspace topology induced as a subset of the usual topology on R
            d) Rl, the lower limit topology on R
            e) The product topology Rl x R
      Prove that X is Hausdorff implies Delta={(x,x) | x in X} is closed in XxX
      (Grad) Delta={(x,x) | x in X} is closed in XxX implies that X is Hausdorff
      p. 159 14 b and c

    Oct 16 - Thur
    • Go over PS 4 Solutions and compare them with your work. Then take WebCT quiz 2 on material up through and including Project 4.

    Oct 14 - Tues
    • Oral test (closed to notes) on material up through and including Project 3. Be sure that you could explain why each answer is true or false from WebCT quiz 1, and that you can explain the answers to test 1.

    Oct 13 - Mon
    • Try 2 of WebCT quiz 1 - see bulletin board message before retaking it.
    • By today, be sure that you have gotten in to see me in office hours for a 10 minute conference.

    Oct 9 - Thur
    • Problem Set 4 p. 34-35
      4, 5, 14, 18
      (Grad) 12 and 17
      Note: On 17 and 18 give informal justifications instead of formal proofs.

    Oct 2 - Thur
    • Test on material up through and including Problem Set 3. Focus on definitions, examples, history, and big picture understanding from class notes and problem set solutions.

    Sept 30 - Tues
    • Take the WebCT quiz. Notes are allowed on this.

    Sep 25 - Thur
    • Problem Set 3 p. 24-26 DUE at 5pm
      5 the first part, 7, 17, 20, 21
      (Grad) 5 the second part about whether Tau is the lower limit topology on R.
      (Grad) 18

    Sep 18 - Thur
    • Read p. 15-19, read through PS 2 solutions and begin working on Problem Set 3.

    Sept 16 - Tues
    Sept 11 - Thur
    • Memorize the definitions of Bd(x,E) and U open in (X,d).
    • Re-read the proof on page 8.

    Sept 9 - Tues
    • Read Patty Section 1.1 and 1.2. Begin working on Problem Set 2.

    Sept 2 - Tues
    Aug 28 - Thur
    • Read handouts given during Tuesday's class. Begin working on Problem Set 1.