Bug reports by Chris Stone

[andrejbauer]

* In Example 1.17, the definition of [[op_i]] is correct just for operations of arity 1. (Also in this definition, L and M are swapped from their order in the rest of the paragraph.)

* In Example 1.30, the map η should take the generator to 1, not 0. (Also, minor inconsistency involving 1 = { () } vs. {*}.)

* In the first and last equations of Example 1.31, the ∧'s should be ∨'s.