Nuprl Lemma : rneq-function
∀f:ℝ ⟶ ℝ. ((∀x,y:ℝ.  ((x = y) 
⇒ (f[x] = f[y]))) 
⇒ (∀x,y:ℝ.  (f[x] ≠ f[y] 
⇒ x ≠ y)))
Proof
Definitions occuring in Statement : 
rneq: x ≠ y
, 
req: x = y
, 
real: ℝ
, 
so_apply: x[s]
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
function: x:A ⟶ B[x]
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
member: t ∈ T
, 
uimplies: b supposing a
, 
prop: ℙ
, 
uall: ∀[x:A]. B[x]
, 
so_apply: x[s]
, 
so_lambda: λ2x.t[x]
, 
or: P ∨ Q
, 
not: ¬A
, 
guard: {T}
, 
false: False
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
Lemmas referenced : 
real-weak-Markov, 
rneq_wf, 
real_wf, 
all_wf, 
req_wf, 
rneq-cases, 
not_wf, 
rneq_irreflexivity, 
rneq_functionality, 
req_weakening
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
hypothesisEquality, 
independent_isectElimination, 
because_Cache, 
hypothesis, 
isectElimination, 
applyEquality, 
functionExtensionality, 
sqequalRule, 
lambdaEquality, 
functionEquality, 
independent_functionElimination, 
unionElimination, 
inlFormation, 
inrFormation, 
voidElimination, 
productElimination
Latex:
\mforall{}f:\mBbbR{}  {}\mrightarrow{}  \mBbbR{}.  ((\mforall{}x,y:\mBbbR{}.    ((x  =  y)  {}\mRightarrow{}  (f[x]  =  f[y])))  {}\mRightarrow{}  (\mforall{}x,y:\mBbbR{}.    (f[x]  \mneq{}  f[y]  {}\mRightarrow{}  x  \mneq{}  y)))
Date html generated:
2017_10_03-AM-09_11_39
Last ObjectModification:
2017_06_26-PM-01_50_51
Theory : reals
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