BT0087

beta_range_entry_eq

Stable checked-use theorem · independently kernel verified

A decoded entry of a Range prefix is its start plus its index.

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.

Exact expanded PA statement

forall b c a l i x. (forall ff_i_entry. (exists ff_lt_entry_bound. ff_lt_entry_bound + S ff_i_entry = l) -> (((exists ff_h_entry_decoded. ff_h_entry_decoded + S (a + ff_i_entry) = S ((S (ff_i_entry)) * c)) /\ exists ff_q_entry_decoded. b = ff_q_entry_decoded * S ((S (ff_i_entry)) * c) + (a + ff_i_entry)))) -> (exists h. h + S i = l) -> (((exists ff_h_range_entry_x. ff_h_range_entry_x + S (x) = S ((S (i)) * c)) /\ exists ff_q_range_entry_x. b = ff_q_range_entry_x * S ((S (i)) * c) + (x))) -> x = a + i

Structural proof guide

A decoded entry of a Range prefix is its start plus its index.

Direct prerequisites: beta_at_unique. The authored body proceeds by intermediate claims (1).

Proof neighborhood

Direct dependencies

BT0042 beta_at_unique

Direct dependents

BT0088 beta_range_transport_entry BT0092 factorial_succ_decompose

Formal native tactic body

Dependencies are hypotheses of the historical Alpha-v12 body receipt. The complete historical Alpha-v18 proof bundle independently checks every dependency; current Alpha v25 preserves that checked theorem use without changing Stable membership.

Read the argument

Proof checkpoints

21 script commands · 3 reading checkpoints · 1 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.

Named ingredients (1)
beta at unique
01Fix variables and assumptionsL1–9

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

  1. L1
    intro b
  2. L2
    intro c
  3. L3
    intro a
  4. L4
    intro l
  5. L5
    intro i
  6. L6
    intro x
  7. L7
    intro hrange
  8. L8
    intro hi
  9. L9
    intro hx
02Establish haL10–19

Establish this local claim before using it. It is not an additional assumption. The following proof commands apply hrange.

  1. L10
    have ha : ((exists h. h + S (a + i) = S ((S i) * c)) /\ exists q. b = q * S ((S i) * c) + (a + i))
  2. L11
    specialize hrange i
  3. L12
    apply hrange
  4. L13
    exact hi
  5. L14
    specialize beta_at_unique b
  6. L15
    specialize beta_at_unique c
  7. L16
    specialize beta_at_unique i
  8. L17
    specialize beta_at_unique x
  9. L18
    specialize beta_at_unique (a + i)
  10. L19
    apply beta_at_unique
03Use earlier factsL20–21

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

  1. L20
    exact hx
  2. L21
    exact ha

Library-wide reading audit

Original exact command ledger · 21 lines
  1. 0001intro b
  2. 0002intro c
  3. 0003intro a
  4. 0004intro l
  5. 0005intro i
  6. 0006intro x
  7. 0007intro hrange
  8. 0008intro hi
  9. 0009intro hx
  10. 0010have ha : ((exists h. h + S (a + i) = S ((S i) * c)) /\ exists q. b = q * S ((S i) * c) + (a + i))
  11. 0011specialize hrange i
  12. 0012apply hrange
  13. 0013exact hi
  14. 0014specialize beta_at_unique b
  15. 0015specialize beta_at_unique c
  16. 0016specialize beta_at_unique i
  17. 0017specialize beta_at_unique x
  18. 0018specialize beta_at_unique (a + i)
  19. 0019apply beta_at_unique
  20. 0020exact hx
  21. 0021exact ha