Rewording.

thesis.tex

@@ -2201,12 +2201,12 @@ interpret an application of $\whoami$.
 \]
 %
 It is not difficult to extend this basic environment model to support
-a more faithful UNIX environment supporting an arbitrary number of
-variables. This can be done by parameterising the $\Ask$ operation by
-some name representation (e.g. a string), which the environment
-handler can use to index into a list of string values. In case the
-name is unbound the environment handler can adopt the lax attitude of
-UNIX and resume with the empty string.
+an arbitrary number of variables. This can be done by parameterising
+the $\Ask$ operation by some name representation (e.g. a string),
+which the environment handler can use to index into a list of string
+values. In case the name is unbound the environment handler can
+embrace UNIX's laissez-faire attitude and resume with the empty
+string.
 
 \paragraph{Session management}