diff --git a/.gitignore b/.gitignore
index 63c56b1..9b83f32 100644
--- a/.gitignore
+++ b/.gitignore
@@ -76,6 +76,7 @@ flycheck_*.el
 # *.ps
 # *.eps
 # *.pdf
+./*.pdf
 
 ## Generated if empty string is given at "Please type another file name for output:"
 .pdf
diff --git a/introduction.pdf b/introduction.pdf
index fc65ac7..cf0e138 100644
Binary files a/introduction.pdf and b/introduction.pdf differ