PA00D4

mod_two_zero_to_even

Alpha v34 checked-use theorem · independently closed; not Stable

Congruence to zero modulo two supplies an even witness.

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 PA statement

forall n. (exists pmt_u_n_zero pmt_v_n_zero. n + 2 * pmt_u_n_zero = 0 + 2 * pmt_v_n_zero) -> (exists pmt_even_n. n = 2 * pmt_even_n)

Structural proof guide

Generated structural guide

Congruence to zero modulo two supplies an even witness.

Use the direct prerequisites mod_eq_zero_to_dvd_nonzero as previously established PA formulas.

The proof proceeds by direct introduction and elimination.

Referenced ingredients

Proof neighborhood

Direct dependencies

Direct dependents

Formal native tactic body

Dependencies are introduced as named hypotheses before line 1. Linked names are exact direct references. This Alpha-v25 checked-use theorem is independently kernel-checked when replayed; it is not a Stable theorem.

Read the argument

Proof checkpoints

9 script commands · 4 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.

Named ingredients (1)
01Fix variables and assumptionsL1–2

Work with arbitrary variables or the premises of the current implication.

  1. L1
    intro n
  2. L2
    intro hzero
02Use earlier factsL3–5

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

  1. L3
    specialize mod_eq_zero_to_dvd_nonzero 2
  2. L4
    specialize mod_eq_zero_to_dvd_nonzero n
  3. L5
    apply mod_eq_zero_to_dvd_nonzero
03Fix variables and assumptionsL6–6

Work with arbitrary variables or the premises of the current implication.

  1. L6
    intro htwo
04Use earlier factsL7–9

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

  1. L7
    apply PA1
  2. L8
    exact htwo
  3. L9
    exact hzero

Library-wide reading audit

Original exact command ledger · 9 lines
  1. 0001intro n
  2. 0002intro hzero
  3. 0003specialize mod_eq_zero_to_dvd_nonzero 2
  4. 0004specialize mod_eq_zero_to_dvd_nonzero n
  5. 0005apply mod_eq_zero_to_dvd_nonzero
  6. 0006intro htwo
  7. 0007apply PA1
  8. 0008exact htwo
  9. 0009exact hzero