Operational Mathematics of the Gamma Function:Extending the Iteration Count to the Complex Domain

This paper systematically transplants the core methodology of Operational Mathematics---the extension of the repetition count of fundamental operations from natural numbers to integers, rational numbers, real numbers, and ultimately complex numbers---onto a new class of transcendental binary operations: the gamma function operation ₙ (a, b) and its inverse ₙ (a, b). A complete set of seven axioms is established, integer-order, fractional-order, real-order, and complex-order iterations are rigorously defined, and the existence of iterative roots at each level is proved by means of Schr\"oder's equation, Abel's equation, and a suitably adapted Kneser construction. Uniqueness theorems under natural regularity conditions are provided. The singularity structure of complex-order gamma iterations is analyzed in depth, revealing a fundamentally novel phenomenon: the branch points are of mixed algebraic (square-root type, from the critical values of) and logarithmic type (from the poles and essential singularity of). The union of these branch points accumulates densely on the negative real axis, forming a natural boundary. The local monodromy group contains both ₂ and factors. A fundamental structural discovery is rigorously proved: the gamma operational hierarchy collapses completely for all levels n 2, leaving only the base operations at level n=1 and the collapsed family at level n=2. Fractional calculus and the fractional calculus of variations with gamma kernels are shown to be special cases of the gamma operational framework, thereby unifying discrete gamma hyperoperations with continuous analysis. A categorical duality between the mathematics of numbers and the mathematics of gamma operations is established, yielding a field isomorphism between the gamma hyperfield and the complex numbers. The connection between gamma iteration values and the arithmetic of the gamma function is explored, with particular emphasis on transcendence of special values and the gamma Riemann Hypothesis, which is proved unconditionally via a Hilbert--P\'olya self-adjoint operator construction applied to the corrected gamma zeta function (defined using backward iterates). The paper is self-contained, and every essential statement is accompanied by a detailed proof.