MV0003

alternating_signed_unit_zero

Public research checkpoint, not admitted to Alpha or Stable. Alpha v30 remains 3222 checked-use theorems; Stable remains 432. The on-demand Alpha Lean service does not yet expose these checkpoint theorems; their independently checked literal bundles and unchanged sources are available below.

Public research checkpoint: original HA and independently compiled Lean verified; not Alpha-enrolled, no Alpha checked-use authority; not Stable

Exponent zero has canonical positive-unit code two, not code one.

Exact expanded first-order arithmetic statement

(((exists mv_even_half_zeroeven. (0) = 2 * mv_even_half_zeroeven) /\ ((2) = 2))) \/ (((exists mv_odd_half_zeroodd. (0) = 2 * mv_odd_half_zeroodd + 1) /\ ((2) = 1)))

Constructive proof overview

Generated structural guide

Exponent zero has canonical positive-unit code two, not code one.

The unchanged tactic script uses 0 declared prerequisites and contains 6 exact native proof lines.

Public research checkpoint: original HA and independently compiled Lean verified; not Alpha-enrolled, no Alpha checked-use authority; not Stable

Proof neighborhood

Direct dependencies

none

Direct dependents

Formal native tactic body

Dependencies are introduced as named hypotheses before line 1. Local theorem links identify exact declared prerequisites. The literal dependency-closed bundle is checked by original HA and the independently compiled Lean verifier. Public delivery grants no Alpha checked-use authority or Stable membership.

Read the argument

Proof checkpoints

6 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.

01Separate the logical casesL1–2

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

  1. L1
    left
  2. L2
    split
02Construct an explicit witnessL3–3

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

  1. L3
    exists 0
03Calculate and transport equalitiesL4–4

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

  1. L4
    symm
04Use earlier factsL5–5

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

  1. L5
    apply PA5
05Calculate and transport equalitiesL6–6

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

  1. L6
    refl

Library-wide reading audit

Original exact command ledger · 6 lines
  1. 0001left
  2. 0002split
  3. 0003exists 0
  4. 0004symm
  5. 0005apply PA5
  6. 0006refl