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 expanded first-order arithmetic statement
forall r e. exists y. (exists dsa_ap_add_solve dsa_an_add_solve dsa_bp_add_solve dsa_bn_add_solve dsa_cp_add_solve dsa_cn_add_solve. (((((r) = 2 * (dsa_ap_add_solve) /\ (dsa_an_add_solve) = 0) \/ exists ge_signed_half_add_solveleft. (((r) = 2 * ge_signed_half_add_solveleft + 1 /\ (dsa_ap_add_solve) = 0) /\ (dsa_an_add_solve) = S ge_signed_half_add_solveleft))) /\ ((((((y) = 2 * (dsa_bp_add_solve) /\ (dsa_bn_add_solve) = 0) \/ exists ge_signed_half_add_solveright. (((y) = 2 * ge_signed_half_add_solveright + 1 /\ (dsa_bp_add_solve) = 0) /\ (dsa_bn_add_solve) = S ge_signed_half_add_solveright))) /\ ((((((e) = 2 * (dsa_cp_add_solve) /\ (dsa_cn_add_solve) = 0) \/ exists ge_signed_half_add_solveoutput. (((e) = 2 * ge_signed_half_add_solveoutput + 1 /\ (dsa_cp_add_solve) = 0) /\ (dsa_cn_add_solve) = S ge_signed_half_add_solveoutput))) /\ ((dsa_ap_add_solve + dsa_bp_add_solve) + dsa_cn_add_solve = (dsa_an_add_solve + dsa_bn_add_solve) + dsa_cp_add_solve)))))))Constructive proof overview
Generated structural guide
Construct the signed addend taking any canonical signed r to any canonical signed e, including zero and negative values.
The unchanged tactic script uses 5 declared prerequisites and contains 26 exact native proof lines.
Alpha v34 checked-use · first admitted v31 · independently kernel and Lean verified; not Stable
Proof neighborhood
Direct dependencies
signed_negate_total Alpha theorem; checked-use authorized signed_add_total Alpha theorem; checked-use authorized signed_add_associative Alpha theorem; checked-use authorized signed_add_negate_right_zero Alpha theorem; checked-use authorized signed_add_zero_left Alpha theorem; checked-use authorizedDirect 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
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 assumptionsL1–2
02Establish hnL3–5
Establish this local claim before using it. It is not an additional assumption. The following proof commands apply signed negate total.
- L3
have hn : ∃ n. ∃ x. ∃ y. SignedDecode(r,x,y) ∧ SignedDecode(n,y,x)Definitions: SignedDecode - L4
specialize signed_negate_total (r) - L5
apply signed_negate_total
03Separate the logical casesL6–6
Follow the explicit conjunction, disjunction, witness, or contradiction step recorded below.
- L6
cases hn
04Establish hyL7–10
05Separate the logical casesL11–11
Follow the explicit conjunction, disjunction, witness, or contradiction step recorded below.
- L11
cases hy
06Construct an explicit witnessL12–12
Supply the displayed value, then prove that it has the required property.
- L12
exists x1
07Use earlier factsL13–22
Instantiate or apply named facts and discharge the corresponding proof obligations.
- L13
specialize signed_add_associative (r) - L14
specialize signed_add_associative (x) - L15
specialize signed_add_associative (e) - L16
specialize signed_add_associative (0) - L17
specialize signed_add_associative (x1) - L18
specialize signed_add_associative (e) - L19
apply signed_add_associative - L20
specialize signed_add_negate_right_zero (r) - L21
specialize signed_add_negate_right_zero (x) - L22
apply signed_add_negate_right_zero
Original exact command ledger · 26 lines
- 0001
intro r - 0002
intro e - 0003
have hn : exists n. (exists mps_positive_solve_negate mps_negative_solve_negate. (((((r) = 2 * (mps_positive_solve_negate) /\ (mps_negative_solve_negate) = 0) \/ exists ge_signed_half_solve_negatesource. (((r) = 2 * ge_signed_half_solve_negatesource + 1 /\ (mps_positive_solve_negate) = 0) /\ (mps_negative_solve_negate) = S ge_signed_half_solve_negatesource))) /\ ((((n) = 2 * (mps_negative_solve_negate) /\ (mps_positive_solve_negate) = 0) \/ exists ge_signed_half_solve_negatetarget. (((n) = 2 * ge_signed_half_solve_negatetarget + 1 /\ (mps_negative_solve_negate) = 0) /\ (mps_positive_solve_negate) = S ge_signed_half_solve_negatetarget))))) - 0004
specialize signed_negate_total (r) - 0005
apply signed_negate_total - 0006
cases hn - 0007
have hy : exists y. (exists dsa_ap_solve_addend dsa_an_solve_addend dsa_bp_solve_addend dsa_bn_solve_addend dsa_cp_solve_addend dsa_cn_solve_addend. (((((x) = 2 * (dsa_ap_solve_addend) /\ (dsa_an_solve_addend) = 0) \/ exists ge_signed_half_solve_addendleft. (((x) = 2 * ge_signed_half_solve_addendleft + 1 /\ (dsa_ap_solve_addend) = 0) /\ (dsa_an_solve_addend) = S ge_signed_half_solve_addendleft))) /\ ((((((e) = 2 * (dsa_bp_solve_addend) /\ (dsa_bn_solve_addend) = 0) \/ exists ge_signed_half_solve_addendright. (((e) = 2 * ge_signed_half_solve_addendright + 1 /\ (dsa_bp_solve_addend) = 0) /\ (dsa_bn_solve_addend) = S ge_signed_half_solve_addendright))) /\ ((((((y) = 2 * (dsa_cp_solve_addend) /\ (dsa_cn_solve_addend) = 0) \/ exists ge_signed_half_solve_addendoutput. (((y) = 2 * ge_signed_half_solve_addendoutput + 1 /\ (dsa_cp_solve_addend) = 0) /\ (dsa_cn_solve_addend) = S ge_signed_half_solve_addendoutput))) /\ ((dsa_ap_solve_addend + dsa_bp_solve_addend) + dsa_cn_solve_addend = (dsa_an_solve_addend + dsa_bn_solve_addend) + dsa_cp_solve_addend))))))) - 0008
specialize signed_add_total (x) - 0009
specialize signed_add_total (e) - 0010
apply signed_add_total - 0011
cases hy - 0012
exists x1 - 0013
specialize signed_add_associative (r) - 0014
specialize signed_add_associative (x) - 0015
specialize signed_add_associative (e) - 0016
specialize signed_add_associative (0) - 0017
specialize signed_add_associative (x1) - 0018
specialize signed_add_associative (e) - 0019
apply signed_add_associative - 0020
specialize signed_add_negate_right_zero (r) - 0021
specialize signed_add_negate_right_zero (x) - 0022
apply signed_add_negate_right_zero - 0023
exact hn_witness - 0024
specialize signed_add_zero_left (e) - 0025
apply signed_add_zero_left - 0026
exact hy_witness