Nuprl Lemma : subtract-is-int-iff
∀[a,b:Base].  uiff(a - b ∈ ℤ;(a ∈ ℤ) ∧ (b ∈ ℤ))
Proof
Definitions occuring in Statement : 
uiff: uiff(P;Q), 
uall: ∀[x:A]. B[x], 
and: P ∧ Q, 
member: t ∈ T, 
subtract: n - m, 
int: ℤ, 
base: Base
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
subtract: n - m, 
uiff: uiff(P;Q), 
and: P ∧ Q, 
uimplies: b supposing a, 
prop: ℙ, 
implies: P ⇒ Q, 
iff: P ⇐⇒ Q, 
rev_implies: P ⇐ Q
Lemmas referenced : 
minus-is-int-iff, 
add-is-int-iff, 
iff_weakening_uiff, 
iff_transitivity, 
uiff_wf, 
base_wf, 
equal-wf-base
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
sqequalRule, 
sqequalHypSubstitution, 
productElimination, 
thin, 
independent_pairEquality, 
isect_memberEquality, 
isectElimination, 
hypothesisEquality, 
axiomEquality, 
equalityTransitivity, 
hypothesis, 
equalitySymmetry, 
lemma_by_obid, 
intEquality, 
baseApply, 
closedConclusion, 
baseClosed, 
because_Cache, 
productEquality, 
independent_pairFormation, 
instantiate, 
cumulativity, 
addLevel, 
independent_isectElimination, 
independent_functionElimination, 
lambdaFormation
Latex:
\mforall{}[a,b:Base].    uiff(a  -  b  \mmember{}  \mBbbZ{};(a  \mmember{}  \mBbbZ{})  \mwedge{}  (b  \mmember{}  \mBbbZ{}))
Date html generated:
2016_05_13-PM-03_28_37
Last ObjectModification:
2016_01_14-PM-06_42_07
Theory : arithmetic
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