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 p a b. (exists ftcn_factor_ftsv_first_divides. (a) = (p) * ftcn_factor_ftsv_first_divides) -> (exists ftcn_factor_ftsv_second_divides. (b) = (p) * ftcn_factor_ftsv_second_divides) -> (exists ftcn_factor_ftsv_square_divides. (a * a + b * b) = (p * p) * ftcn_factor_ftsv_square_divides)Constructive proof overview
Generated structural guide
Any common coordinate divisor has its square as an actual divisor of the two-square norm.
The unchanged tactic script uses 1 declared prerequisite and contains 18 exact native proof lines.
dependency-curried kernel-checked theorem body; Alpha enrollment and checked-use authority follow separately sealed release evidence; Stable membership remains unchanged
Proof neighborhood
Direct dependencies
Direct dependents
Formal native tactic body
Dependencies are introduced as named hypotheses before line 1. Local theorem links identify exact declared prerequisites. This dependency-curried candidate body does not grant checked theorem use or Stable membership.
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 (1)
01Fix variables and assumptionsL1–5
02Establish hextractionL6–12
Establish this local claim before using it. It is not an additional assumption. The following proof commands apply two square common divisor extracts squared factor.
- L6
have hextraction : exists ftsv_first_extracted ftsv_second_extracted. ((a = p * ftsv_first_extracted) /\ ((b = p * ftsv_second_extracted) /\ (a * a + b * b = (p * p) * (ftsv_first_extracted * ftsv_first_extracted + ftsv_second_extracted * ftsv_second_extracted)))) - L7
specialize two_square_common_divisor_extracts_squared_factor p - L8
specialize two_square_common_divisor_extracts_squared_factor a - L9
specialize two_square_common_divisor_extracts_squared_factor b - L10
apply two_square_common_divisor_extracts_squared_factor - L11
exact hfirst - L12
exact hsecond
03Separate the logical casesL13–16
04Construct an explicit witnessL17–17
Supply the displayed value, then prove that it has the required property.
- L17
exists x * x + x1 * x1
05Use earlier factsL18–18
Instantiate or apply named facts and discharge the corresponding proof obligations.
- L18
exact hextraction_witness_witness_right_right
Original exact command ledger · 18 lines
- 0001
intro p - 0002
intro a - 0003
intro b - 0004
intro hfirst - 0005
intro hsecond - 0006
have hextraction : exists ftsv_first_extracted ftsv_second_extracted. ((a = p * ftsv_first_extracted) /\ ((b = p * ftsv_second_extracted) /\ (a * a + b * b = (p * p) * (ftsv_first_extracted * ftsv_first_extracted + ftsv_second_extracted * ftsv_second_extracted)))) - 0007
specialize two_square_common_divisor_extracts_squared_factor p - 0008
specialize two_square_common_divisor_extracts_squared_factor a - 0009
specialize two_square_common_divisor_extracts_squared_factor b - 0010
apply two_square_common_divisor_extracts_squared_factor - 0011
exact hfirst - 0012
exact hsecond - 0013
cases hextraction - 0014
cases hextraction_witness - 0015
cases hextraction_witness_witness - 0016
cases hextraction_witness_witness_right - 0017
exists x * x + x1 * x1 - 0018
exact hextraction_witness_witness_right_right