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 initial 0/1 convergent is included: u is natural, not necessarily positive. Comparison denominators are strictly smaller and positive. Signed competitors are represented by an arbitrary difference rp−rn. Approximation inequalities are proved from the trace, never stored as assumptions in Convergent.
Exact theorem in conservative defined notation
∀ a. ∀ b. ∀ s. ∀ i. ∀ u. ∀ v. ContinuedFraction(a,b,s) → Convergent(s,i,u,v) → SignedBestApproximationSecondKind(a,b,u,v)
Every linked abbreviation expands hygienically to the identical original native formula.
Definition DAG
Actual proof prerequisites
Complete tactic proof in conservative notation
All 61 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
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 (2)
01Fix variables and assumptionsL1–10
02Fix variables and assumptionsL11–17
03Separate the logical casesL18–27
Follow the explicit conjunction, disjunction, witness, or contradiction step recorded below.
- L18
cases hcf - L19
cases hcf_witness - L20
cases hcf_witness_witness - L21
cases hcf_witness_witness_witness - L22
cases hcf_witness_witness_witness_witness - L23
cases hcf_witness_witness_witness_witness_witness - L24
cases hcf_witness_witness_witness_witness_witness_right - L25
cases hconv - L26
cases hconv_witness - L27
cases hconv_witness_witness
04Separate the logical casesL28–29
05Use earlier factsL30–39
Instantiate or apply named facts and discharge the corresponding proof obligations.
- L30
specialize cf_approximation_derived_invariant_best_signed (a) - L31
specialize cf_approximation_derived_invariant_best_signed (b) - L32
specialize cf_approximation_derived_invariant_best_signed (u) - L33
specialize cf_approximation_derived_invariant_best_signed (x5) - L34
specialize cf_approximation_derived_invariant_best_signed (v) - L35
specialize cf_approximation_derived_invariant_best_signed (x6) - L36
specialize cf_approximation_derived_invariant_best_signed (rp) - L37
specialize cf_approximation_derived_invariant_best_signed (rn) - L38
specialize cf_approximation_derived_invariant_best_signed (t) - L39
specialize cf_approximation_derived_invariant_best_signed (C)
06Use earlier factsL40–49
Instantiate or apply named facts and discharge the corresponding proof obligations.
- L40
specialize cf_approximation_derived_invariant_best_signed (D) - L41
apply cf_approximation_derived_invariant_best_signed - L42
specialize cf_convergent_actual_prefix_error_invariant (i) - L43
specialize cf_convergent_actual_prefix_error_invariant (a) - L44
specialize cf_convergent_actual_prefix_error_invariant (b) - L45
specialize cf_convergent_actual_prefix_error_invariant (s) - L46
specialize cf_convergent_actual_prefix_error_invariant (x2) - L47
specialize cf_convergent_actual_prefix_error_invariant (x3) - L48
specialize cf_convergent_actual_prefix_error_invariant (S x4) - L49
specialize cf_convergent_actual_prefix_error_invariant (x7)
07Use earlier factsL50–59
Instantiate or apply named facts and discharge the corresponding proof obligations.
- L50
specialize cf_convergent_actual_prefix_error_invariant (x8) - L51
specialize cf_convergent_actual_prefix_error_invariant (u) - L52
specialize cf_convergent_actual_prefix_error_invariant (x5) - L53
specialize cf_convergent_actual_prefix_error_invariant (v) - L54
specialize cf_convergent_actual_prefix_error_invariant (x6) - L55
apply cf_convergent_actual_prefix_error_invariant - L56
exact hcf_witness_witness_witness_witness_witness_right_right - L57
exact hconv_witness_witness_witness_witness_right - L58
exact ht - L59
exact hlt
Original defined command ledger · 61 lines
- 0001
intro a - 0002
intro b - 0003
intro s - 0004
intro i - 0005
intro u - 0006
intro v - 0007
intro hcf - 0008
intro hconv - 0009
intro rp - 0010
intro rn - 0011
intro t - 0012
intro C - 0013
intro D - 0014
intro ht - 0015
intro hlt - 0016
intro hc - 0017
intro hd - 0018
cases hcf - 0019
cases hcf_witness - 0020
cases hcf_witness_witness - 0021
cases hcf_witness_witness_witness - 0022
cases hcf_witness_witness_witness_witness - 0023
cases hcf_witness_witness_witness_witness_witness - 0024
cases hcf_witness_witness_witness_witness_witness_right - 0025
cases hconv - 0026
cases hconv_witness - 0027
cases hconv_witness_witness - 0028
cases hconv_witness_witness_witness - 0029
cases hconv_witness_witness_witness_witness - 0030
specialize cf_approximation_derived_invariant_best_signed (a) - 0031
specialize cf_approximation_derived_invariant_best_signed (b) - 0032
specialize cf_approximation_derived_invariant_best_signed (u) - 0033
specialize cf_approximation_derived_invariant_best_signed (x5) - 0034
specialize cf_approximation_derived_invariant_best_signed (v) - 0035
specialize cf_approximation_derived_invariant_best_signed (x6) - 0036
specialize cf_approximation_derived_invariant_best_signed (rp) - 0037
specialize cf_approximation_derived_invariant_best_signed (rn) - 0038
specialize cf_approximation_derived_invariant_best_signed (t) - 0039
specialize cf_approximation_derived_invariant_best_signed (C) - 0040
specialize cf_approximation_derived_invariant_best_signed (D) - 0041
apply cf_approximation_derived_invariant_best_signed - 0042
specialize cf_convergent_actual_prefix_error_invariant (i) - 0043
specialize cf_convergent_actual_prefix_error_invariant (a) - 0044
specialize cf_convergent_actual_prefix_error_invariant (b) - 0045
specialize cf_convergent_actual_prefix_error_invariant (s) - 0046
specialize cf_convergent_actual_prefix_error_invariant (x2) - 0047
specialize cf_convergent_actual_prefix_error_invariant (x3) - 0048
specialize cf_convergent_actual_prefix_error_invariant (S x4) - 0049
specialize cf_convergent_actual_prefix_error_invariant (x7) - 0050
specialize cf_convergent_actual_prefix_error_invariant (x8) - 0051
specialize cf_convergent_actual_prefix_error_invariant (u) - 0052
specialize cf_convergent_actual_prefix_error_invariant (x5) - 0053
specialize cf_convergent_actual_prefix_error_invariant (v) - 0054
specialize cf_convergent_actual_prefix_error_invariant (x6) - 0055
apply cf_convergent_actual_prefix_error_invariant - 0056
exact hcf_witness_witness_witness_witness_witness_right_right - 0057
exact hconv_witness_witness_witness_witness_right - 0058
exact ht - 0059
exact hlt - 0060
exact hc - 0061
exact hd