BT008K · Bertrand theorem

all_bits_last_succ

Stable checked-use theorem · independently kernel verified

The final entry of a nonempty all-bits prefix is zero or one.

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.

Statement with defined notation

∀ b. ∀ c. ∀ l. ∀ sl. sl = S l → AllBits(b,c,sl) → ∃ x. BetaAt(b,c,l,x) ∧ (x = 0 ∨ x = 1)

Every purple notation token opens its conservative definition. Expanding the displayed statement recovers the exact first-order Peano-arithmetic formula checked by the unchanged kernel.

Definitions used by this theorem

In the theorem statement

2 occurrences

In local proof propositions

none

0 occurrences

Exact expanded native-PA statement
forall b c l sl. sl = S l -> (forall ff_i_successor. (exists ff_lt_successor_bound. ff_lt_successor_bound + S ff_i_successor = sl) -> exists ff_bit_successor. ((((exists ff_h_successor_decoded. ff_h_successor_decoded + S (ff_bit_successor) = S ((S (ff_i_successor)) * c)) /\ exists ff_q_successor_decoded. b = ff_q_successor_decoded * S ((S (ff_i_successor)) * c) + (ff_bit_successor))) /\ (ff_bit_successor = 0 \/ ff_bit_successor = 1))) -> exists a. ((((exists ff_h_last. ff_h_last + S (a) = S ((S (l)) * c)) /\ exists ff_q_last. b = ff_q_last * S ((S (l)) * c) + (a))) /\ (a = 0 \/ a = 1))

Proof neighborhood

Direct theorem prerequisites

Direct theorem dependents

Definition-aware tactic body

Only local propositions introduced by have or suffices are compacted. Every changed line has an exact-AST conservative-expansion receipt; the kernel still receives the immutable original tactic script.

Read the argument

Proof checkpoints

11 script commands · 3 reading checkpoints · 0 local claims

This is a reading aid, not a new proof or a proof-tree certificate. Checkpoint groups are consecutive commands, not inferred branch boundaries. Every step links to the preserved script.

Definition notation is shown below. Open the paired exact edition for the original native formulas. Source pairing is not a new equivalence certificate.

Named ingredients (1)
01Fix variables and assumptionsL1–6

Work with arbitrary variables or the premises of the current implication.

  1. L1
    intro b
  2. L2
    intro c
  3. L3
    intro l
  4. L4
    intro sl
  5. L5
    intro hsl
  6. L6
    intro hbits
02Calculate and transport equalitiesL7–7

Carry out the recorded arithmetic or equality steps; inspect the exact commands for their direction and premises.

  1. L7
    rewrite hsl at hbits
03Use earlier factsL8–11

Instantiate or apply named facts and discharge the corresponding proof obligations.

  1. L8
    specialize hbits l
  2. L9
    apply hbits
  3. L10
    specialize le_refl (S l)
  4. L11
    exact le_refl

Library-wide reading audit

Original defined command ledger · 11 lines
  1. 0001intro b
  2. 0002intro c
  3. 0003intro l
  4. 0004intro sl
  5. 0005intro hsl
  6. 0006intro hbits
  7. 0007rewrite hsl at hbits
  8. 0008specialize hbits l
  9. 0009apply hbits
  10. 0010specialize le_refl (S l)
  11. 0011exact le_refl