--- a/README.md
+++ b/README.md
@@ -21,7 +21,7 @@
 using the command "polymake" at the Linux prompt. A few (optional) 
 functions rely on Singular software (available from 
 https://www.singular.uni-kl.de/) which should be installed so that it starts 
-using the command "singular" at the Linux prompt. A few (oprional) functions
+using the command "singular" at the Linux prompt. A few (optional) functions
 rely on Graphviz software (available from http://www.graphviz.org/).
 
 Please send your bug reports to graham.ellis(at)nuigalway.ie .
--- a/doc/newNewCellComplexes.xml
+++ b/doc/newNewCellComplexes.xml
@@ -11799,7 +11799,7 @@
 <Description><P/>
 
 <P/>Displays a barcode  
-<B>L=PersitentBettiNumbers(X,n)</B>.
+<B>L=PersistentBettiNumbers(X,n)</B>.
 
  <P/><B>Examples:</B> <URL><Link>../tutorial/chap10.html</Link><LinkText>1</LinkText></URL>&nbsp;,
 <URL><Link>../www/SideLinks/About/aboutPersistent.html</Link><LinkText>2</LinkText></URL>&nbsp; 
@@ -11934,7 +11934,7 @@
 <Description><P/>
 
 <P/>Displays a barcode  
-<B>L=PersitentBettiNumbers(X,n)</B> in compact form.
+<B>L=PersistentBettiNumbers(X,n)</B> in compact form.
 
  <P/><B>Examples:</B> <URL><Link>../tutorial/chap5.html</Link><LinkText>1</LinkText></URL>&nbsp;,
 <URL><Link>../tutorial/chap10.html</Link><LinkText>2</LinkText></URL>&nbsp;,
--- a/tutorial/tutex/14.20.txt
+++ b/tutorial/tutex/14.20.txt
@@ -1,6 +1,6 @@
 gap> R:=ResolutionArtinGroup(D,8);
 Resolution of length 8 in characteristic 0 for &lt;fp group on the generators 
-[ f1, f2, f3, f4, f5, f6, f7 ]&gr; . 
+[ f1, f2, f3, f4, f5, f6, f7 ]&gt; . 
 No contracting homotopy available. 
 
 gap> Size(R);
