Life of Fred Metamathematics $49 : The subfields of math.  Turing machines definition.  Adding, subtracting, recognizing more than two symbols.  The impossibility of locating all the non-blank symbols on an input tape.  Turing machines with two tracks.  With two tapes.  Unary notation.  The universal computer.  Turing machines on an infinite checkerboard instead of a tape.  The halting problem.  Dealing with negative numbers, copying a number, multiplying, exponentiation, projection and constant functions, determining if x > y.  Doing logic computations.  Doing geometry.  True vs. provable.  Gödel's First and Second Incompleteness Theorems.  Computable functions defined.  The Church-Turing thesis.  Primitive recursive functions.  General recursive functions.  The Ackermann function.  Self-replicating machines.  P and NP functions. ISBN: 978-1-937032-63-0, hardback, 128 pages.  $49