ND0233

AlternatingSignedUnit(n,z)

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.

The actual signed code of (-1)^n from parity: even exponents give code 2 (+1), odd exponents code 1 (-1).

Conservative notation; not a theorem, primitive, or axiom.

Definition in prerequisite notation

Even(n) ∧ z = 2 ∨ Odd(n) ∧ z = 1

Only definitions earlier in this acyclic notation graph are used here.

Hygienic expanded first-order definition 
(((exists mv_even_half_bottomlayereven. ((n)) = 2 * mv_even_half_bottomlayereven) /\ (((z)) = 2))) \/ (((exists mv_odd_half_bottomlayerodd. ((n)) = 2 * mv_odd_half_bottomlayerodd + 1) /\ (((z)) = 1)))

The unchanged native kernel never receives this surface symbol. Binder-safe expansion produces only its existing first-order syntax.

Direct definition dependencies

Even(n)Odd(n)

Definitions depending on this notation

FactorParitySign(n,z)

Checked theorems using this definition

none directly; see definition consumers