BA0003

cf_approximation_prepend_error_forward

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

A true Euclidean division transports one signed numerator error exactly.

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 q r x y e. a = b * q + r -> b * y = r * x + e -> b * (q * x + y) = a * x + e

Constructive proof overview

Generated structural guide

A true Euclidean division transports one signed numerator error exactly.

The unchanged tactic script uses 6 declared prerequisites and contains 14 exact native proof lines.

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

Proof neighborhood

Direct dependencies

add_mul Stable theorem; checked-use authorized mul_add Stable theorem; checked-use authorized mul_assoc Stable theorem; checked-use authorized mul_comm Stable theorem; checked-use authorized add_assoc Stable theorem; checked-use authorized add_comm Stable theorem; checked-use authorized

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

14 script commands · 4 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 q
  4. L4
    intro r
  5. L5
    intro x
  6. L6
    intro y
  7. L7
    intro e
  8. L8
    intro ha
  9. L9
    intro he
02Calculate and transport equalitiesL10–10

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

  1. L10
    trans b * (q * x) + b * y
03Use earlier factsL11–11

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

  1. L11
    apply mul_add
04Calculate and transport equalitiesL12–14

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

  1. L12
    rewrite he
  2. L13
    rewrite ha
  3. L14
    simp [add_mul, mul_add, mul_assoc, mul_comm, add_assoc, add_comm]

Library-wide reading audit

Original exact command ledger · 14 lines
  1. 0001intro a
  2. 0002intro b
  3. 0003intro q
  4. 0004intro r
  5. 0005intro x
  6. 0006intro y
  7. 0007intro e
  8. 0008intro ha
  9. 0009intro he
  10. 0010trans b * (q * x) + b * y
  11. 0011apply mul_add
  12. 0012rewrite he
  13. 0013rewrite ha
  14. 0014simp [add_mul, mul_add, mul_assoc, mul_comm, add_assoc, add_comm]