cr.yp.to update

 2005-261.html |   43 +++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 43 insertions(+)
diff -ru .old-crypto/2005-261.html cr.yp.to/2005-261.html
--- .old-crypto/2005-261.html	2005-09-09 22:29:55.000000000 -0400
+++ cr.yp.to/2005-261.html	2005-09-18 10:29:54.000000000 -0400
@@ -391,5 +391,48 @@
 <p>
 <b>The first exam will be Monday 19 September.</b>
 It will cover sets, functions, and Boolean functions.
+<h2>18 September 2005</h2>
+Class material from Monday:
+The Boolean function ^ (``and'') is the function from {0,1}x{0,1} to {0,1}
+defined as follows:
+^(0,0) = 0;
+^(0,1) = 0;
+^(1,0) = 0;
+^(1,1) = 1.
+Repeated in standard notation:
+0^0 = 0;
+0^1 = 0;
+1^0 = 0;
+1^1 = 1.
+The Boolean function v (``or'') is the function from {0,1}x{0,1} to {0,1}
+defined as follows:
+0v0 = 0;
+0v1 = 1;
+1v0 = 1;
+1v1 = 1.
+The Boolean function ~ (``not'') is the function from {0,1} to {0,1}
+defined as follows:
+~0 = 1;
+~1 = 0.
+The Boolean function xor is the function from {0,1}x{0,1} to {0,1}
+defined as follows:
+0 xor 0 = 0;
+0 xor 1 = 1;
+1 xor 0 = 1;
+1 xor 1 = 0.
+In mathematics, ``a or b'' means ``a or b or both,''
+while ``either a or b'' means ``either a or b but not both.''
+The Boolean function =&gt; (``implies'')
+is the function from {0,1}x{0,1} to {0,1}
+defined as follows:
+0=&gt;0 = 1;
+0=&gt;1 = 1;
+1=&gt;0 = 0;
+1=&gt;1 = 1.
+Building more complicated functions;
+examples of truth tables.
+<p>
+Wednesday and Friday were review.
+Good luck on the exam!
 </body>
 </html>