%In this file enter, in the order you wish them to appear %in your exam, each exam problem. The \problem command sequence %has three parameters, thus \problem{#1}{#2}{#3}, %where #3 is the problem itself, and must be a single paragraph %(so don't have any blank lines in it; you can use \vskip0in %to get the effect of a new paragraph). Parameter #2 should %be a number; it specifies how many inches of vertical space %should be skipped following the problem (thereby leaving %space for the students to get their answer). Parameter #1 %is the point value of the problem. %There is also another command that can be used: \comment{#1}{#2}, %which inserts whatever you enter for parameter #2, and skips %a space in inches specified by #1. Use the comment command to insert %a short stretch of material that is not a problem, for example %a section header, to divide the exam up into parts. Note that %\comment behaves exactly the same as \problem except that it involves no %problem number nor a point value. In particular, if your comment will not %fit in the space remaining on the page, then the whole comment is %put on the next page. \comment{.2}{Section I} \problem{20}{.2}{Let $X$ be a topological space, and let $A$ be a subset of $X$. Let ${\cal T}_A'$ be the collection of all open subsets $U$ of $X$ such that either $U$ is empty or $U$ meets $A$. Let ${\cal T}_A''$ be the collection of all open subsets $U$ of $X$ such that either $U$ is empty or $U$ contains $A$. \vskip0in Give a proof or a counterexample for each of the following two statements: \itemitem{(a)} The collection ${\cal T}_A'$ is a topology on $X$. \itemitem{(b)} The collection ${\cal T}_A''$ is a topology on $X$.} \comment{.2}{Section II} \problem{20}{.2}{Give a proof or a counterexample for each of the following two statements: \itemitem{(a)} Let $X$ and $Y$ be metric spaces with finitely many points. Then any bijective map from $X$ to $Y$ is a homeomorphism. \itemitem{(b)} Any bijective, continuous map of topological spaces is a homeomorphism.} \comment{.2}{Section III} \problem{20}{.2}{Give an example of a {\scaleby{1440} big} category and then solve {\scaleby{\magstep3} $x3z=\Gamma$}.} \problem{20}{.2}{Find the determinant of the following matrix: $$A=\left(\matrix{x & 1\cr x & 1\cr x & 1\cr x & 1\cr x & 1\cr x & 1\cr x & 1\cr x & 1\cr x & 1\cr x & 1\cr x & 1\cr x & 1\cr x & 1\cr x & 1\cr x & 1\cr}\right)$$}