HL000C

beta_horner_root_mod_weaken

A witnessed root modulo a multiple is also a root modulo the old divisor.

Alpha v34 checked-use · first admitted v27 · 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.

The derivative-nonzero criterion supplies no inverse or power witness: both are constructed. Roots may be arbitrary natural representatives of signed integer polynomials. Singular-root classification and p-adic completion are separate milestones.

Exact theorem in conservative defined notation

∀ b. ∀ c. ∀ a. ∀ l. ∀ m. ∀ M. Dvd(m,M) → HornerRootModulo(b,c,a,l,M) → HornerRootModulo(b,c,a,l,m)

Every linked abbreviation expands hygienically to the identical original native formula.

Definition DAG

HornerRootModulo(b,c,a,l,m) · 2Dvd(d,n) · 1

Actual proof prerequisites

mod_eq_of_mod_eq_multiple · checked external prerequisite
Original expanded first-order statement 
forall b c a l m M. (exists q. M = m * q) -> (exists hpl_value_root. ((exists ff_u_ph_hpl_root ff_v_ph_hpl_root. ((((exists fs_h_ph_hpl_root_body_start. fs_h_ph_hpl_root_body_start + S (0) = S ((S (0)) * ff_v_ph_hpl_root)) /\ exists fs_q_ph_hpl_root_body_start. ff_u_ph_hpl_root = fs_q_ph_hpl_root_body_start * S ((S (0)) * ff_v_ph_hpl_root) + (0))) /\ ((((exists fs_h_ph_hpl_root_body_terminal. fs_h_ph_hpl_root_body_terminal + S (hpl_value_root) = S ((S (l)) * ff_v_ph_hpl_root)) /\ exists fs_q_ph_hpl_root_body_terminal. ff_u_ph_hpl_root = fs_q_ph_hpl_root_body_terminal * S ((S (l)) * ff_v_ph_hpl_root) + (hpl_value_root))) /\ forall ff_i_ph_hpl_root_body_steps. (exists ph_bound_hpl_root_body_steps. ph_bound_hpl_root_body_steps + S ff_i_ph_hpl_root_body_steps = l) -> exists ff_coefficient_ph_hpl_root_body_steps ff_previous_ph_hpl_root_body_steps ff_current_ph_hpl_root_body_steps. ((((exists fs_h_ph_hpl_root_body_steps_coefficient. fs_h_ph_hpl_root_body_steps_coefficient + S (ff_coefficient_ph_hpl_root_body_steps) = S ((S (ff_i_ph_hpl_root_body_steps)) * c)) /\ exists fs_q_ph_hpl_root_body_steps_coefficient. b = fs_q_ph_hpl_root_body_steps_coefficient * S ((S (ff_i_ph_hpl_root_body_steps)) * c) + (ff_coefficient_ph_hpl_root_body_steps))) /\ ((((exists fs_h_ph_hpl_root_body_steps_before. fs_h_ph_hpl_root_body_steps_before + S (ff_previous_ph_hpl_root_body_steps) = S ((S (ff_i_ph_hpl_root_body_steps)) * ff_v_ph_hpl_root)) /\ exists fs_q_ph_hpl_root_body_steps_before. ff_u_ph_hpl_root = fs_q_ph_hpl_root_body_steps_before * S ((S (ff_i_ph_hpl_root_body_steps)) * ff_v_ph_hpl_root) + (ff_previous_ph_hpl_root_body_steps))) /\ ((((exists fs_h_ph_hpl_root_body_steps_after. fs_h_ph_hpl_root_body_steps_after + S (ff_current_ph_hpl_root_body_steps) = S ((S (S ff_i_ph_hpl_root_body_steps)) * ff_v_ph_hpl_root)) /\ exists fs_q_ph_hpl_root_body_steps_after. ff_u_ph_hpl_root = fs_q_ph_hpl_root_body_steps_after * S ((S (S ff_i_ph_hpl_root_body_steps)) * ff_v_ph_hpl_root) + (ff_current_ph_hpl_root_body_steps))) /\ ff_current_ph_hpl_root_body_steps = ff_previous_ph_hpl_root_body_steps * a + ff_coefficient_ph_hpl_root_body_steps)))))) /\ (exists hgcrt_mod_left_hpl_root hgcrt_mod_right_hpl_root. hpl_value_root + M * hgcrt_mod_left_hpl_root = 0 + M * hgcrt_mod_right_hpl_root))) -> (exists hpl_value_root. ((exists ff_u_ph_hpl_root ff_v_ph_hpl_root. ((((exists fs_h_ph_hpl_root_body_start. fs_h_ph_hpl_root_body_start + S (0) = S ((S (0)) * ff_v_ph_hpl_root)) /\ exists fs_q_ph_hpl_root_body_start. ff_u_ph_hpl_root = fs_q_ph_hpl_root_body_start * S ((S (0)) * ff_v_ph_hpl_root) + (0))) /\ ((((exists fs_h_ph_hpl_root_body_terminal. fs_h_ph_hpl_root_body_terminal + S (hpl_value_root) = S ((S (l)) * ff_v_ph_hpl_root)) /\ exists fs_q_ph_hpl_root_body_terminal. ff_u_ph_hpl_root = fs_q_ph_hpl_root_body_terminal * S ((S (l)) * ff_v_ph_hpl_root) + (hpl_value_root))) /\ forall ff_i_ph_hpl_root_body_steps. (exists ph_bound_hpl_root_body_steps. ph_bound_hpl_root_body_steps + S ff_i_ph_hpl_root_body_steps = l) -> exists ff_coefficient_ph_hpl_root_body_steps ff_previous_ph_hpl_root_body_steps ff_current_ph_hpl_root_body_steps. ((((exists fs_h_ph_hpl_root_body_steps_coefficient. fs_h_ph_hpl_root_body_steps_coefficient + S (ff_coefficient_ph_hpl_root_body_steps) = S ((S (ff_i_ph_hpl_root_body_steps)) * c)) /\ exists fs_q_ph_hpl_root_body_steps_coefficient. b = fs_q_ph_hpl_root_body_steps_coefficient * S ((S (ff_i_ph_hpl_root_body_steps)) * c) + (ff_coefficient_ph_hpl_root_body_steps))) /\ ((((exists fs_h_ph_hpl_root_body_steps_before. fs_h_ph_hpl_root_body_steps_before + S (ff_previous_ph_hpl_root_body_steps) = S ((S (ff_i_ph_hpl_root_body_steps)) * ff_v_ph_hpl_root)) /\ exists fs_q_ph_hpl_root_body_steps_before. ff_u_ph_hpl_root = fs_q_ph_hpl_root_body_steps_before * S ((S (ff_i_ph_hpl_root_body_steps)) * ff_v_ph_hpl_root) + (ff_previous_ph_hpl_root_body_steps))) /\ ((((exists fs_h_ph_hpl_root_body_steps_after. fs_h_ph_hpl_root_body_steps_after + S (ff_current_ph_hpl_root_body_steps) = S ((S (S ff_i_ph_hpl_root_body_steps)) * ff_v_ph_hpl_root)) /\ exists fs_q_ph_hpl_root_body_steps_after. ff_u_ph_hpl_root = fs_q_ph_hpl_root_body_steps_after * S ((S (S ff_i_ph_hpl_root_body_steps)) * ff_v_ph_hpl_root) + (ff_current_ph_hpl_root_body_steps))) /\ ff_current_ph_hpl_root_body_steps = ff_previous_ph_hpl_root_body_steps * a + ff_coefficient_ph_hpl_root_body_steps)))))) /\ (exists hgcrt_mod_left_hpl_root hgcrt_mod_right_hpl_root. hpl_value_root + m * hgcrt_mod_left_hpl_root = 0 + m * hgcrt_mod_right_hpl_root)))

Complete tactic proof in conservative notation

All 20 original proof lines are preserved. Only local proposition formulas are abbreviated; every abbreviation has an exact binder-safe expansion check. The linked exact edition contains the unchanged replay script.

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.

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

01Fix variables and assumptionsL1–8

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 m
  6. L6
    intro M
  7. L7
    intro hdiv
  8. L8
    intro hroot
02Separate the logical casesL9–10

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

  1. L9
    cases hroot
  2. L10
    cases hroot_witness
03Construct an explicit witnessL11–11

Supply the displayed value, then prove that it has the required property.

  1. L11
    exists x
04Separate the logical casesL12–12

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

  1. L12
    split
05Use earlier factsL13–20

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

  1. L13
    exact hroot_witness_left
  2. L14
    specialize mod_eq_of_mod_eq_multiple m
  3. L15
    specialize mod_eq_of_mod_eq_multiple M
  4. L16
    specialize mod_eq_of_mod_eq_multiple x
  5. L17
    specialize mod_eq_of_mod_eq_multiple 0
  6. L18
    apply mod_eq_of_mod_eq_multiple
  7. L19
    exact hdiv
  8. L20
    exact hroot_witness_right

Library-wide reading audit

Original defined command ledger · 20 lines
  1. 0001intro b
  2. 0002intro c
  3. 0003intro a
  4. 0004intro l
  5. 0005intro m
  6. 0006intro M
  7. 0007intro hdiv
  8. 0008intro hroot
  9. 0009cases hroot
  10. 0010cases hroot_witness
  11. 0011exists x
  12. 0012split
  13. 0013exact hroot_witness_left
  14. 0014specialize mod_eq_of_mod_eq_multiple m
  15. 0015specialize mod_eq_of_mod_eq_multiple M
  16. 0016specialize mod_eq_of_mod_eq_multiple x
  17. 0017specialize mod_eq_of_mod_eq_multiple 0
  18. 0018apply mod_eq_of_mod_eq_multiple
  19. 0019exact hdiv
  20. 0020exact hroot_witness_right