\magnification = \magstep1
\nopagenumbers
\leftline{Mathematics 243 -- Algebraic Structures}
\leftline{Definitions Quiz 7 -- October 27, 2006}
\medskip
\leftline{Your Name: $\underline{\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ }$}
\bigskip
\noindent
A) (5)  What is the definition of the relation $x \equiv y \bmod n$ for integers $x,y,n$?

\vglue 4.0truein
\noindent
B) (5)  Let $f$ be the mapping that takes an integer $x$ to its
congruence class mod 23:  $f(x) = [x]$ for the congruence mod 23 relation.  
Is $f$ a one-to-one mapping?  Is $f$ an onto mapping to the set of all
congruence classes mod 23?
\bye
