This work develops Neural Network Meta-Operational Mathematics, a comprehensive and rigorous framework that elevates neural network operations themselves to the status of independent mathematical objects. Every fundamental operation of deep learning—forward propagation, backpropagation, activation functions, loss functions, optimizers (SGD, Adam), batch normalization, dropout, convolution, pooling, residual connections, attention mechanisms, Transformers—is treated as a first-class operation in a suitably defined space. Their compositional inverses (transposed convolution, unpooling, inverse propagation, inverse optimizer steps) are also incorporated, forming natural inverse pairs. The core philosophical principle—operations can be operated upon—is realized through a four-level hierarchy: Level 0 consists of elementary tensors (weights, biases, activations); Level 1 consists of neural network operations as smooth maps on the base space; Level 2 consists of meta-operations (maps that take operations to operations); Level 3 and higher consist of iterated meta-operations. The number of iterations (compositions, exponentiations, logarithms) can be integer, fractional, real, complex, or even infinite. We establish an axiomatic system of eleven axioms and prove its relative consistency and independence. The space NN(F) of smooth neural network operations is equipped with a bornological norm ∥·∥B; we prove its bornological completeness, providing a rigorous foundation for infinite sums, infinite compositions, transfinite iterations, and fractional iterates. The category NNCat is shown to be a monoidal closed category, and a Stone-type duality between NNCat and the opposite category of classical computation graphs is established via cuts and lifts. A quantitative analysis of collapse phenomena caused by non-idempotent operations (e.g., dropout, decaying learning rates, batch normalization) is given, including explicit convergence rates, collapse of relational powers to the diagonal, and collapse of transfinite compositions to the zero operation. Weighted parametrized neural network operations and L-fuzzy hyperdomains are developed. The neural network path integral is reinterpreted as a Gaussian expectation, connecting to classical special functions and to the Connes-Kreimer renormalization Hopf algebra via an explicit Hopf algebra morphism. All classical special functions that appear as activation functions (error function, GELU, Swish, etc.) are shown to belong to the meta-operational universe, and their fundamental identities become equations of meta-operations. The entire framework is categorified to a strict 2-category 2NNCat and further to a quasi-category (∞-category). Numerical algorithms (automatic neural network differentiation, truncated exponential series, continued fractions, maximal solution iteration for neural relation equations) are provided with rigorous error bounds. All previously stated conjectures are either resolved as theorems or explicitly marked as open with partial progress. This work provides a unified language connecting deep learning, analysis, algebra, geometry, topology, and renormalization theory.
Liu S (Wed,) studied this question.