Nuprl Lemma : not-discontinuous

[f:ℝ ⟶ ℝ]. ∀[x:ℝ]. discontinuous(f;x)) supposing ∀x,y:ℝ.  ((x y)  ((f x) (f y)))


Proof




Definitions occuring in Statement :  discontinuous: discontinuous(f;x) req: y real: uimplies: supposing a uall: [x:A]. B[x] all: x:A. B[x] not: ¬A implies:  Q apply: a function: x:A ⟶ B[x]
Definitions unfolded in proof :  uall: [x:A]. B[x] member: t ∈ T uimplies: supposing a not: ¬A implies:  Q false: False prop: so_lambda: λ2x.t[x] so_apply: x[s] discontinuous: discontinuous(f;x) exists: x:A. B[x] all: x:A. B[x] subtype_rel: A ⊆B rfun: I ⟶ℝ top: Top and: P ∧ Q iff: ⇐⇒ Q rev_implies:  Q less_than: a < b squash: T less_than': less_than'(a;b) true: True rsub: y real-fun: real-fun(f;a;b) guard: {T} real-cont: real-cont(f;a;b) cand: c∧ B sq_stable: SqStable(P) uiff: uiff(P;Q) rev_uimplies: rev_uimplies(P;Q) le: A ≤ B rge: x ≥ y rgt: x > y nat_plus: + rneq: x ≠ y or: P ∨ Q rless: x < y sq_exists: x:{A| B[x]} decidable: Dec(P) satisfiable_int_formula: satisfiable_int_formula(fmla)
Lemmas referenced :  discontinuous_wf real_wf all_wf req_wf real-fun-iff-continuous rsub_wf int-to-real_wf radd_wf member_rccint_lemma subtype_rel_dep_function rleq_wf subtype_rel_self set_wf radd-preserves-rless rless-int rminus_wf rless_wf rless_functionality req_weakening radd-int radd_functionality radd-zero-both req_transitivity radd-rminus-both radd-rminus-assoc radd-ac radd_comm req_inversion radd-assoc i-member_wf rccint_wf small-reciprocal-real rmin_wf rmin_strict_ub sq_stable__rless radd-preserves-rleq rmul_wf rleq-int false_wf uiff_transitivity rleq_functionality rminus-as-rmul rmul-identity1 rmul-distrib2 rmul_functionality uiff_transitivity2 rmul-zero-both squash_wf true_wf rminus-int rabs-difference-bound-iff rleq_functionality_wrt_implies rleq_weakening_equal rleq_weakening_rless rmin-rleq radd_functionality_wrt_rless2 rabs_wf rdiv_wf nat_plus_properties decidable__lt satisfiable-full-omega-tt intformand_wf intformnot_wf intformless_wf itermConstant_wf itermVar_wf int_formula_prop_and_lemma int_formula_prop_not_lemma int_formula_prop_less_lemma int_term_value_constant_lemma int_term_value_var_lemma int_formula_prop_wf rless_transitivity2 rless_transitivity1 rless_irreflexivity
Rules used in proof :  sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity isect_memberFormation introduction cut lambdaFormation thin because_Cache hypothesis sqequalHypSubstitution independent_functionElimination voidElimination extract_by_obid isectElimination functionExtensionality applyEquality hypothesisEquality sqequalRule lambdaEquality dependent_functionElimination isect_memberEquality functionEquality equalityTransitivity equalitySymmetry productElimination natural_numberEquality independent_isectElimination voidEquality setEquality productEquality setElimination rename independent_pairFormation imageMemberEquality baseClosed addEquality addLevel levelHypothesis dependent_set_memberEquality imageElimination minusEquality promote_hyp inrFormation unionElimination dependent_pairFormation int_eqEquality intEquality computeAll

Latex:
\mforall{}[f:\mBbbR{}  {}\mrightarrow{}  \mBbbR{}].  \mforall{}[x:\mBbbR{}].  (\mneg{}discontinuous(f;x))  supposing  \mforall{}x,y:\mBbbR{}.    ((x  =  y)  {}\mRightarrow{}  ((f  x)  =  (f  y)))



Date html generated: 2016_10_26-AM-09_51_59
Last ObjectModification: 2016_08_12-PM-07_25_27

Theory : reals


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