Nuprl Lemma : subtract_nat_wf

∀[i,j:ℤ].  i - j ∈ ℕ supposing j ≤ i


Proof




Definitions occuring in Statement :  nat: ℕ,  uimplies: b supposing a,  uall: ∀[x:A]. B[x],  le: A ≤ B,  member: t ∈ T,  subtract: n - m,  int: ℤ
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  member: t ∈ T,  uimplies: b supposing a,  nat: ℕ,  le: A ≤ B,  and: P ∧ Q,  subtract: n - m,  prop: ℙ,  all: ∀x:A. B[x],  subtype_rel: A ⊆r B,  top: Top,  uiff: uiff(P;Q),  nat_plus: ℕ+,  less_than: a < b,  squash: ↓T,  less_than': less_than'(a;b),  true: True,  implies: P ⇒ Q,  not: ¬A,  false: False,  decidable: Dec(P),  or: P ∨ Q
Lemmas referenced :  subtract_wf,  minus-one-mul,  le_wf,  istype-int,  add_functionality_wrt_le,  le_reflexive,  minus-one-mul-top,  istype-void,  one-mul,  add-swap,  add-commutes,  add-associates,  add-mul-special,  two-mul,  mul-distributes-right,  zero-mul,  zero-add,  not-le-2,  minus-zero,  add-zero,  omega-shadow,  less_than_wf,  mul-distributes,  mul-associates,  mul-commutes,  le-add-cancel-alt,  decidable__le
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  Error :isect_memberFormation_alt,  introduction,  cut,  Error :dependent_set_memberEquality_alt,  extract_by_obid,  sqequalHypSubstitution,  isectElimination,  thin,  hypothesisEquality,  hypothesis,  productElimination,  sqequalRule,  Error :universeIsType,  natural_numberEquality,  axiomEquality,  equalityTransitivity,  equalitySymmetry,  Error :isect_memberEquality_alt,  because_Cache,  Error :inhabitedIsType,  multiplyEquality,  independent_isectElimination,  dependent_functionElimination,  applyEquality,  Error :lambdaEquality_alt,  voidElimination,  addEquality,  minusEquality,  independent_pairFormation,  imageMemberEquality,  baseClosed,  independent_functionElimination,  unionElimination

Latex:
\mforall{}[i,j:\mBbbZ{}].    i  -  j  \mmember{}  \mBbbN{}  supposing  j  \mleq{}  i



Date html generated: 2019_06_20-AM-11_26_25
Last ObjectModification: 2018_10_03-AM-10_13_23

Theory : arithmetic


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