BA0022

cf_approximation_errors_exchange_columns

Alpha v34 independently verified · alpha_closed; checked-use authorized; not Stable

Exchanging adjacent vectors exchanges their actual error magnitudes and reverses their signs.

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 first-order arithmetic statement

forall a b u U v V E F. (((a * v = b * u + E) /\ (b * U = a * V + F)) \/ ((b * u = a * v + E) /\ (a * V = b * U + F))) -> (((a * V = b * U + F) /\ (b * u = a * v + E)) \/ ((b * U = a * V + F) /\ (a * v = b * u + E)))

Constructive proof overview

Generated structural guide

Exchanging adjacent vectors exchanges their actual error magnitudes and reverses their signs.

The unchanged tactic script uses 0 declared prerequisites and contains 20 exact native proof lines.

Alpha v34 checked-use · first admitted v29 · independently kernel and Lean verified; not Stable

Proof neighborhood

Direct dependencies

none

Direct dependents

Formal native tactic body

Dependencies are introduced as named hypotheses before line 1. Local theorem links identify exact declared prerequisites. This exact body belongs to a complete independently kernel-checked constructive proof bundle and has Alpha checked-use authority; it does not imply Stable membership.

Read the argument

Proof checkpoints

20 script commands · 5 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.

01Fix variables and assumptionsL1–9

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

  1. L1
    intro a
  2. L2
    intro b
  3. L3
    intro u
  4. L4
    intro U
  5. L5
    intro v
  6. L6
    intro V
  7. L7
    intro E
  8. L8
    intro F
  9. L9
    intro h
02Separate the logical casesL10–13

Follow the explicit conjunction, disjunction, witness, or contradiction step recorded below.

  1. L10
    cases h
  2. L11
    cases h_left
  3. L12
    right
  4. L13
    split
03Use earlier factsL14–15

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

  1. L14
    exact h_left_right
  2. L15
    exact h_left_left
04Separate the logical casesL16–18

Follow the explicit conjunction, disjunction, witness, or contradiction step recorded below.

  1. L16
    cases h_right
  2. L17
    left
  3. L18
    split
05Use earlier factsL19–20

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

  1. L19
    exact h_right_right
  2. L20
    exact h_right_left

Library-wide reading audit

Original exact command ledger · 20 lines
  1. 0001intro a
  2. 0002intro b
  3. 0003intro u
  4. 0004intro U
  5. 0005intro v
  6. 0006intro V
  7. 0007intro E
  8. 0008intro F
  9. 0009intro h
  10. 0010cases h
  11. 0011cases h_left
  12. 0012right
  13. 0013split
  14. 0014exact h_left_right
  15. 0015exact h_left_left
  16. 0016cases h_right
  17. 0017left
  18. 0018split
  19. 0019exact h_right_right
  20. 0020exact h_right_left