Nuprl Lemma : qminus-qsub
∀[r,s:ℚ].  (-(s - r) = (r - s) ∈ ℚ)
Proof
Definitions occuring in Statement : 
qsub: r - s
, 
qmul: r * s
, 
rationals: ℚ
, 
uall: ∀[x:A]. B[x]
, 
minus: -n
, 
natural_number: $n
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
subtype_rel: A ⊆r B
, 
true: True
, 
qsub: r - s
, 
squash: ↓T
, 
prop: ℙ
, 
and: P ∧ Q
, 
uimplies: b supposing a
, 
guard: {T}
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
implies: P 
⇒ Q
Lemmas referenced : 
rationals_wf, 
int-subtype-rationals, 
qmul_wf, 
qadd_wf, 
equal_wf, 
squash_wf, 
true_wf, 
qmul_over_plus_qrng, 
qinv_inv_q, 
qadd_comm_q, 
iff_weakening_equal
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
hypothesis, 
extract_by_obid, 
sqequalRule, 
sqequalHypSubstitution, 
isect_memberEquality, 
isectElimination, 
thin, 
hypothesisEquality, 
axiomEquality, 
because_Cache, 
minusEquality, 
natural_numberEquality, 
applyEquality, 
lambdaEquality, 
imageElimination, 
equalityTransitivity, 
equalitySymmetry, 
universeEquality, 
productElimination, 
imageMemberEquality, 
baseClosed, 
independent_isectElimination, 
independent_functionElimination
Latex:
\mforall{}[r,s:\mBbbQ{}].    (-(s  -  r)  =  (r  -  s))
Date html generated:
2018_05_21-PM-11_51_51
Last ObjectModification:
2017_07_26-PM-06_44_43
Theory : rationals
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