On Carryless Pairing.
The algorithm bellow emerges solely from addition and bounded recursion. We demonstrate the core mechanism and the pairing function.
(i) First, a chosen set of Fibonacci terms is aggregated into a single numerical value.
(ii) In a second step, the selection itself is discarded, and only the resulting sum is returned to a Greedy Algorithm.
(iii) Finally, the original terms are recovered from the sum alone within a bounded number of steps.
This round-trip, from arbitrary input to canonical additive and back, utilizes Binet’s Formula, the Hurwitz Satz, and Zeckendorf’s Theorem to yield a stable, reversible, and fully bounded finitary encoding–decoding scheme.
(iv) The structure can be used to realize a constructive (hence injective) arithmetical pairing function:
Step 1. We select (at least 2) integers that our javascript decomposes uniquely into non-consecutive Fibonacci summands.
Step 2. We forget the supporting Fibonacci indices...
...and reconstruct them via a series of local search problems.
Step 3. We can use this correspondance to create an injective $\Delta_0$ pairing function. We select 2 arbitrary natural numbers.
$x \in \mathbb{N}:$
$y \in \mathbb{N}:$
Step 4. Inverse is given by bounded search in subpolynomial-time.
$n \in \mathbb{N}:$
Remark. The pairing $\pi_{\mathrm{CL}}^\tau$ is finitary and correctness relies on the uniqueness and stability of Zeckendorf decompositions (cf. 'Phi'-adic Logic) under exact order. The apperant division at the reversal is a $\mathcal{O}(\log n)$ search problem. However, if one realizes the procedure in a numerical model that is not an exact copy of $\{\,\mathbb{N},\, +,\, \le\,\}$ (with $\Delta I$) then the underlying invariants might not be preserved, e.g. IEEE-754 floating-point past $2^{53}$. This highlights a persistent key bias in contemporary computation.
Acknoledgment. Thanks are due to Albert Visser University of Utrecht for timely criticism and guidance.