Transputation: Quantum Measurement at Turing Degree Exactly 0-prime

This tutorial explains one of the most surprising results in the GTE framework: quantum measurement has a precise location in the mathematical hierarchy of computational difficulty. It sits at exactly one level above an ordinary Turing machine — no more, no less. That level is Turing degree 0' (zero-prime), the halting problem. This is a theorem machine-certified in Lean 4 with zero sorry, not a metaphor. The result, called Transputation, shows that the Born-rule probability update during quantum measurement is exactly as hard to compute as the halting problem: it is decidable given an oracle for the halting problem, but not by any ordinary Turing machine. This tutorial explains the computability classification, the GTE derivation that places measurement at degree 0', and the physical interpretation of why quantum indeterminacy sits at precisely this level of the arithmetical hierarchy.