175, 275 -Homework 11 and suggestions for the week after Thanksgiving

Homework 11 is due Tuesday, December 2, at the beginning of lecture. The usual considerations apply.

In 175 we will try to cover this week until section 8.10, but probably won’t get that far. As mentioned last week, we will also cover additional topics that the book doesn’t mention or doesn’t treat in sufficient detail, once we are done with 8.10. These topics are uniform vs. pointwise convergence (including Wierstrass test), the behavior of the -series for , and infinite products. I will distribute notes of the topics not covered in the book. If you want to read ahead, and would like some of the notes ahead of time, please let me know.

In 275 we will cover Chapter 14, probably this week we will cover until section 14.4. Particularly important are the notion of conservative field and Green’s theorem. Then we will continue with surface integrals and orientations, Stokes’s and the divergence theorems. This will probably take another week, maybe a bit more. If there is any time left afterwards, we will see Lagrange multipliers

Homework 11:

175: Do not use the solutions manual for any of these problems.

Turn in the problems listed for Homework 10 that you still have pending.

Section 8.6. Exercises 8, 25, 28, 37, 60.

Section 8.7. Exercises 2, 4, 39-48.

Besides the exercises you have pending from last week, there are 17 new problems. Turn in the exercises you have pending, and at least 10 of the new problems. The others (at most 7) will be due December 9, together with the additional exercises for that week.

275:

Turn in the problems listed for Homework 10 that you still have pending.

Section 14.1. Exercises 1-8, 12, 16, 29.

Section 14.2. Exercises 6, 8, 34, 41.

Section 14.3. Exercises 2, 6, 12, 17, 20, 34, 38.

Section 14.4. Exercises 2, 8, 18, 31-35.

Exercises 14.1.1-8 count as a single exercise. Besides the problems pending from last week, there are 23 exercises. Turn in at least 10 of these. The remaining problems (at most 13) will be due together with a few additional exercises on December 9.

A database of number fields, by Jürgen Klüners and Gunter Malle. (Note this is not the same as the one mentioned in this answer.) The site also provides links to similar databases.

As the other answer indicates, the yes answer to your question is known as the De Bruijn-Erdős theorem. This holds regardless of the size of the graph. The De Bruijn–Erdős theorem is a particular instance of what in combinatorics we call a compactness argument or Rado's selection principle, and its truth can be seen as a consequence of the topological c […]

Every $P_c$ has the size of the reals. For instance, suppose $\sum_n a_n=c$ and start by writing $\mathbb N=A\cup B$ where $\sum_{n\in A}a_n$ converges absolutely (to $a$, say). This is possible because $a_n\to 0$: Let $m_0

Consider a subset $\Omega$ of $\mathbb R$ of size $\aleph_1$ and ordered in type $\omega_1$. (This uses the axiom of choice.) Let $\mathcal F$ be the $\sigma$-algebra generated by the initial segments of $\Omega$ under the well-ordering (so all sets in $\mathcal F$ are countable or co-countable), with the measure that assigns $0$ to the countable sets and $1 […]

You assume $\omega_\alpha\subseteq M$ and $X\in M$ so that $X$ belongs to the transitive collapse of $M$ (because if $\pi$ is the collapsing map, $\pi(X)=\pi[X]=X$. You assume $|M|=\aleph_\alpha$ so that the transitive collapse of $M$ has size $\aleph_\alpha$. Since you also have that this transitive collapse is of the form $L_\beta$ for some $\beta$, it fol […]

No, this is not possible. Dave L. Renfro wrote an excellent historical Essay on nowhere analytic $C^\infty$ functions in two parts (with numerous references). See here: 1 (dated May 9, 2002 6:18 PM), and 2 (dated May 19, 2002 8:29 PM). As indicated in part 1, in Zygmunt Zahorski. Sur l'ensemble des points singuliers d'une fonction d'une variab […]

I don't think you need too much in terms of prerequisites. An excellent reference is MR3616119. Tomkowicz, Grzegorz(PL-CEG2); Wagon, Stan(1-MACA-NDM). The Banach-Tarski paradox. Second edition. With a foreword by Jan Mycielski. Encyclopedia of Mathematics and its Applications, 163. Cambridge University Press, New York, 2016. xviii+348 pp. ISBN: 978-1-10 […]

For the second problem, write $x=-3+x'$ and so on. You have $x'+y'+z'=17$ and $x',\dots$ are nonnegative, a case you know how to solve. You can also solve the first problem this way; now you would set $x=1+x'$, etc.