ℕ↪ℤ↪ℚ↪ℝ↪ℂ
Topic 001 · Standalone Paper
Working Paper · 2026
The Complete Bounded Number Chain

Bounded Number Theory

The complete number chain ℕ_B(k) ↪ ℤ_B(k) ↪ ℚ_B(k²) ↪ ℝ_B(k) ↪ ℂ_B(k⁴), constructed from Bounded Set Theory alone. Exact arithmetic on discrete systems. Precision-parameterised identities on continuous systems. Every object finite, every cardinality bounded, every construction verified through the nine BFTs. The Cayley-Dickson extensions to bounded quaternions and octonions are available at the algebraic level.

Prerequisite
BST only — single dependency
Systems built
ℕ_B, ℤ_B, ℚ_B, ℝ_B, ℂ_B + ℍ_B, 𝕆_B
Engine
BI-BST + BR-BST
Governing model
𝒱_{k⁴+8} contains all
Supersedes
AFB Parts VI – VIII

The complete bounded number chain.

ℕ_B(k)
Naturals
ℤ_B(k)
Integers
ℚ_B(k²)
Rationals
ℝ_B(k)
Reals
ℂ_B(k⁴)
Complex
Each embedding is injective and structure-preserving. The parameter growth (k, k, k², k, k⁴) reflects the combinatorial cost of each construction. For any k, the standard model 𝒱_{k⁴+8} contains the entire chain.

Each built on the last. Each verified within the standard models.

Discrete systems (ℕ, ℤ, ℚ) have exact arithmetic on interior elements. Continuous systems (ℝ, ℂ) have rational computation followed by rounding, with grid displacement bounded by O(1/k²) per operation.

ℕ_B(k)
Bounded Naturals
Exact

Von Neumann ordinals {0, 1, ..., k}. Arithmetic by bounded recursion. Unique factorisation, GCD, Bezout, primality — all by BI-BST with finite search.

ℤ_B(k)
Bounded Integers
Exact

Pairs of naturals modulo (a,b) ~ (c,d) iff a+d = b+c. Equivalence checked in ℕ_B(2k). Ring axioms on the interior domain. Integers from −k to +k.

ℚ_B(k²)
Bounded Rationals
Exact

Fraction pairs modulo ad = bc, checked in ℤ_B(k²). Field axioms on the interior domain. k²-dense: no gap exceeds 1/k² (Farey sequence argument).

ℝ_B(k)
Bounded Reals
Precision 1/k

Cauchy sequences rounded to nearest rational via ρ_k. Equivalence by exact identity ρ_k(s) = ρ_k(t). k-complete: every Cauchy sequence has a limit. Commutativity exact; associativity at O(1/k²).

ℂ_B(k⁴)
Bounded Complex
Precision 1/k

ℝ_B(k) × ℝ_B(k). Standard complex arithmetic with rounding. i² = (−1, 0) exact. Non-orderable. Algebraic closure for degrees 1–4 by explicit formulas.

Exact equivalence at every quotient stage.

At each quotient stage of the chain, equivalence is defined by exact identification computed within the model's resources. If any equivalence were approximate, the embeddings would fail. Exact equivalence is a structural requirement, not a convenience.

Stage
Exact condition
Equality checked in
Intermediate computation
ℤ_B(k)
a + d = b + c
ℕ_B(2k)
ℕ_B(2k)
ℚ_B(k)
a · d = b · c
ℤ_B(k²)
ℤ_B(k²)
ℝ_B(k)
ρ_k(s) = ρ_k(t)
ℚ_B(k)
ℚ_B(k²) for rounding

What makes the chain work.

Principle 01

The "within domain" pattern

At each quotient stage, equivalence is defined by exact identification computed within the model's resources. The pattern is uniform: exact equality, trivially transitive, no approximate threshold. This is forced by BST's requirement that all constructions use decidable conditions on interior elements.

Principle 02

The interiority cascade

Each construction consumes a bounded number of rank levels. The super-exponential growth of the cumulative hierarchy (1, 2, 4, 16, 65536, ...) ensures room for the next construction. For any k, 𝒱_{k⁴+8} contains the entire chain with all components interior.

Principle 03

Explicit precision

On discrete systems, arithmetic is exact for interior results. On continuous systems, every operation produces a definite value and the grid displacement is bounded: ≤ 1/(2k²) per operation for associativity, ≤ C/k² for distributivity. The precision parameter is the mathematical content.

Three types of recovery, strictly ordered by strength.

Every major result from the number chain is classified. Most are Type I.

I
Internal Exact

BST proves the theorem outright

No precision parameters, no family indexing. The theorem is simply true within the bounded system about its own objects.

Unique factorisation · Lagrange · CRT
Fermat's Little Theorem · Quadratic reciprocity
Commutativity of + and × (all systems)
Additive/multiplicative identities and inverses
II
Uniform Family

Proved at each precision level k

BST proves the theorem at each k with stable form across the family. The classical theorem is the schema the instances share.

k-completeness of ℝ_B(k)
Density of ℚ_B(k) (k²-dense for each k)
Embedding chain preservation
III
Precision-Parameterised

Explicit grid displacement

BST proves the theorem at each k with an explicit precision parameter quantifying the grid displacement. The parameter is the mathematical content — it reports what computation actually produces.

Associativity of + and × (ℝ, ℂ) — ≤ 1/(2k²)
Distributivity (ℝ, ℂ) — ≤ C/k²
Multiplicative inverses (ℝ, ℂ) — ≤ O(1/k²)

Cayley-Dickson extensions — algebraically available.

The Cayley-Dickson construction iterates the Cartesian product with modified multiplication. At each step, an algebraic property is lost. The loss is a feature of the construction, not of the bounded setting.

ℂ_B(k⁴)
Complex
Loses ordering
ℍ_B(k⁸)
Quaternions
Loses commutativity
𝕆_B(k¹⁶)
Octonions
Loses associativity

The number chain is established.

Every object finite, every cardinality bounded, every construction verified. The analytical apparatus over ℝ_B(k) and ℂ_B(k⁴) — continuity, differentiation, integration, convergence, transcendental functions — belongs to the main paper, The Axiom of Finite Bounds.

Read the Paper (PDF) Download PDF
Working Paper · 2026
Supersedes AFB Parts VI – VIII
"Every verified proof in mathematics is a finite derivation over finite symbols. BST makes this finiteness explicit rather than suppressing it behind an infinite ontology." — Bounded Number Theory, Working Paper 2026