Current library: Alpha v34, 4,223 checked-use theorems; Stable remains 432. Historical first admissions, original proof editions, and non-admitted aliases are preserved.
For an actual table an inverse exists exactly when N=0 or F(1) is signed +1 or -1. At a positive window this is the unit-at-one criterion; the empty window imposes no condition at one. Every inverse has actual delta and two-sided convolution witnesses. Its zeroth value is arbitrary, so uniqueness is positive-value equality, not equality of codes or of zeroth values. Multiplicative-function closure and full finite signed G009 are admitted in the separate Alpha-v32 multiplicative-convolution family.
Exact theorem in conservative defined notation
∀ F. DirichletUnitAtOne(F) → ∃ x. ArithAt(F,1,x) ∧ SignedUnit(x)
Every linked abbreviation expands hygienically to the identical original native formula.
Definition DAG
Actual proof prerequisites
Complete tactic proof in conservative notation
All 13 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.
01Fix variables and assumptionsL1–2
02Separate the logical casesL3–3
Follow the explicit conjunction, disjunction, witness, or contradiction step recorded below.
- L3
cases hu
03Construct an explicit witnessL4–4
Supply the displayed value, then prove that it has the required property.
- L4
exists 2
04Separate the logical casesL5–5
Follow the explicit conjunction, disjunction, witness, or contradiction step recorded below.
- L5
split
05Use earlier factsL6–6
Instantiate or apply named facts and discharge the corresponding proof obligations.
- L6
exact hu_left
06Separate the logical casesL7–7
Follow the explicit conjunction, disjunction, witness, or contradiction step recorded below.
- L7
left
07Calculate and transport equalitiesL8–8
Carry out the recorded arithmetic or equality steps; inspect the exact commands for their direction and premises.
- L8
refl
08Construct an explicit witnessL9–9
Supply the displayed value, then prove that it has the required property.
- L9
exists 1
09Separate the logical casesL10–10
Follow the explicit conjunction, disjunction, witness, or contradiction step recorded below.
- L10
split
10Use earlier factsL11–11
Instantiate or apply named facts and discharge the corresponding proof obligations.
- L11
exact hu_right
11Separate the logical casesL12–12
Follow the explicit conjunction, disjunction, witness, or contradiction step recorded below.
- L12
right
12Calculate and transport equalitiesL13–13
Carry out the recorded arithmetic or equality steps; inspect the exact commands for their direction and premises.
- L13
refl