
diff -r 4f422766763f -r 82d0a2aa1849 handouts/notation.tex
--- a/handouts/notation.tex	Fri Sep 05 16:59:48 2025 +0100
+++ b/handouts/notation.tex	Fri Sep 05 18:24:39 2025 +0100
@@ -10,7 +10,7 @@
 
 \section*{A Crash-Course on Notation}
 
-There are an innumerable number of books available on compilers, automata theory
+There are innumerable books available on compilers, automata theory
 and formal languages. Unfortunately, they often use their own
 notational conventions and their own symbols. This handout is meant to
 clarify some of the notation I will use. I apologise in advance that
@@ -116,7 +116,7 @@
 \dq{\textit{foobar}}. But as said above, we will often
 simplify our life and just drop the double quotes whenever it
 is clear we are talking about strings. So we will just
-write \textit{foo}, \textit{bar}, \textit{foobar} 
+write \textit{foo}, \textit{bar}, \textit{foobar}, 
 \textit{foo $@$ bar} and so on.
 
 Occasionally we will use the notation $a^n$ for strings, which stands
@@ -254,13 +254,22 @@
 
 \noindent
 contain actually the same amount of elements. Does this make sense to you?
-If yes, good. If not, then something to learn about.
+If yes, good. If not, then something to learn about. 
 
-Though this might all look strange, infinite sets will be a
-topic that is very relevant to the material of this module. It tells
-us what we can compute with a computer (actually an algorithm) and what
-we cannot. But during the first 9 lectures we can go by without this
-``weird'' stuff. End of aside.\smallskip
+Though this might all look strange, infinite sets will be a topic that
+is very relevant to the material of this module. It tells us what we
+can compute with a computer (actually an algorithm) and what we
+cannot. But during the first 9 lectures we can go by without this
+``weird'' stuff. \textbf{Update:} Unfortunately we have now so much
+material about compilers in the module that I needed to drop this
+lecture about infinite sets. This is really a pity because notions
+like infinity (and decidability) play important roles in compilers as
+soon as one goes beyond the basics. Fortunately you can get pretty much 
+the same
+material from very slick videos produced by the Youtube channel Veritasium
+(\textit{How An Infinite Hotel Ran Out Of
+  Room}).\video{https://www.youtube.com/watch?v=OxGsU8oIWjY} End of
+aside.\smallskip
 
 Another important notion in this module are \defn{languages}, which
 are sets of strings. One of the main goals for us will be how to
@@ -380,8 +389,8 @@
 \noindent
 Thanks for making it until here! There are also some personal conventions
 about regular expressions. But I will explain them in the handout for the
-first week. An exercise you can do: Implement the power operation for languages
-and try out some examples.
+first week. An exercise you can do: Implement the power operation 
+for languages in your preferred programming language and try out some examples.
 \end{document}
 
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