ND0005

SignedDet2(a,b,c,d,p,n)

The exact positive and negative natural components p=ad and n=bc of a signed 2×2 determinant.

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

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.

Hygienic expanded first-order definition

p = a * d /\ n = b * c

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

Direct definition dependencies

none — first-order arithmetic only

Definitions depending on this notation

none

Checked theorems using this definition

none directly; see definition consumers

Separate complete second-wave branches: Full T13 proof · Alpha v27.