Constructive binary length and powers of two — Exact Proof Explorer

Twenty-one independently checked constructive theorems prove unique binary digit decomposition, strict power-of-two growth, and existence and uniqueness of the exact canonical bit length for every natural number.

21 theorem bodies · 50 proof edges · 542 tactic lines · 5 layers

Alpha v34 checked-use · first admitted v22 · independently kernel and Lean verified; not Stable

Current library: Alpha v34, 4,223 checked-use theorems; Stable remains 432. Historical first admissions, original proof editions, and non-admitted aliases are preserved. Exact original first-admission records.

21 theorems
01234
BL0001 · binary_length_digit_bounded

Every witnessed binary digit is strictly below two.

layer 0 · 9 lines · Alpha v34 independently verified · alpha_closed; checked-use authorized; not Stable
BL0002 · binary_length_digit_split_exists

Every natural number has an exact binary quotient and zero-or-one digit.

layer 0 · 3 lines · Alpha v34 independently verified · alpha_closed; checked-use authorized; not Stable
BL0005 · binary_power_two_exists

Every natural exponent has a witnessed beta-coded power of two.

layer 0 · 4 lines · Alpha v34 independently verified · alpha_closed; checked-use authorized; not Stable
BL0006 · binary_power_two_functional

The relational power of two is functional at every exponent.

layer 0 · 12 lines · Alpha v34 independently verified · alpha_closed; checked-use authorized; not Stable
BL0007 · binary_power_two_zero_value

The beta-coded zeroth power of two is exactly one.

layer 0 · 8 lines · Alpha v34 independently verified · alpha_closed; checked-use authorized; not Stable
BL0008 · binary_power_two_nonzero

Every beta-coded power of two is constructively nonzero.

layer 0 · 12 lines · Alpha v34 independently verified · alpha_closed; checked-use authorized; not Stable
BL0009 · binary_power_two_successor_double

A successor power of two is exactly the sum of two predecessor powers.

layer 0 · 20 lines · Alpha v34 independently verified · alpha_closed; checked-use authorized; not Stable
BL000C · binary_power_two_exponent_strict

Strictly ordered exponents have strictly ordered powers of two.

layer 2 · 33 lines · Alpha v34 independently verified · alpha_closed; checked-use authorized; not Stable
BL000D · binary_length_zero

The blueprint convention gives zero exactly one displayed binary digit.

layer 0 · 4 lines · Alpha v34 independently verified · alpha_closed; checked-use authorized; not Stable
BL000E · binary_length_one

The positive integer one has exactly one binary digit.

layer 1 · 41 lines · Alpha v34 independently verified · alpha_closed; checked-use authorized; not Stable
BL000F · binary_length_zero_input_value

Any binary-length witness for zero is necessarily one.

layer 0 · 18 lines · Alpha v34 independently verified · alpha_closed; checked-use authorized; not Stable
BL0010 · binary_length_successor_step

A binary-length witness for n constructively produces one for S n.

layer 2 · 75 lines · Alpha v34 independently verified · alpha_closed; checked-use authorized; not Stable
BL0011 · binary_length_exists

Every natural number has a constructively witnessed canonical bit length.

layer 3 · 8 lines · Alpha v34 independently verified · alpha_closed; checked-use authorized; not Stable
BL0012 · binary_length_zero_input_general

Any canonical bit-length witness at an input equal to zero is one.

layer 1 · 11 lines · Alpha v34 independently verified · alpha_closed; checked-use authorized; not Stable
BL0013 · binary_length_functional

Two complete constructive binary-length witnesses for one input agree.

layer 2 · 120 lines · Alpha v34 independently verified · alpha_closed; checked-use authorized; not Stable
BL0014 · binary_length_exists_unique

Every natural has exactly one canonical blueprint-compatible bit length.

layer 4 · 14 lines · Alpha v34 independently verified · alpha_closed; checked-use authorized; not Stable
BL0015 · binary_length_power_exact

The exact beta-coded power 2^e has canonical binary length e+1.

layer 2 · 40 lines · Alpha v34 independently verified · alpha_closed; checked-use authorized; not Stable

Exactly 21 displayed theorems have independently verified Alpha checked-use authority; none is admitted to Stable. Body-only enrollment never grants checked theorem use.