@@ -27,7 +27,7 @@ type and ``n`` is the length of the list and can be an arbitrary term.
2727When types can contain values, and where those values describe
2828properties, for example the length of a list, the type of a function
2929can begin to describe its own properties. Take for example the
30−concatenatation of two lists. This operation has the property that the
30+concatenation of two lists. This operation has the property that the
3131resulting list's length is the sum of the lengths of the two input
3232lists. We can therefore give the following type to the ``app``
3333function, which concatenates vectors: