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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