ND0237

Unit(a,m)

Exactly m>1 with a witnessed inverse b<m and a*b congruent to one. Unlike the old UnitResidue range, this expresses genuine invertibility at composite moduli.

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.

Definition in prerequisite notation

Lt(1,m) ∧ (∃ x. Lt(x,m)ModEq(m,a · x,1))

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

Hygienic expanded first-order definition
(exists eut_gap_eu_bottomlayer_domain. eut_gap_eu_bottomlayer_domain + S (1) = ((m))) /\ exists eu_inverse_bottomlayer. (exists eut_gap_eu_bottomlayer_bound. eut_gap_eu_bottomlayer_bound + S (eu_inverse_bottomlayer) = ((m))) /\ (exists eu_mod_left_bottomlayer_inverse eu_mod_right_bottomlayer_inverse. (((a))*eu_inverse_bottomlayer) + ((m)) * eu_mod_left_bottomlayer_inverse = (1) + ((m)) * eu_mod_right_bottomlayer_inverse)

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

Direct definition dependencies

Definitions depending on this notation

none

Checked theorems using this definition