Nuprl Lemma : rless-cases

x,y:ℝ.  ((x < y)  (∀z:ℝ((x < z) ∨ (z < y))))


Proof




Definitions occuring in Statement :  rless: x < y real: all: x:A. B[x] implies:  Q or: P ∨ Q
Definitions unfolded in proof :  member: t ∈ T rless-cases-proof rless-iff8 decidable__lt decidable__squash uall: [x:A]. B[x] so_lambda: so_lambda(x,y,z,w.t[x; y; z; w]) so_apply: x[s1;s2;s3;s4] top: Top uimplies: supposing a strict4: strict4(F) and: P ∧ Q all: x:A. B[x] implies:  Q has-value: (a)↓ prop: guard: {T} or: P ∨ Q squash: T so_lambda: λ2y.t[x; y] so_apply: x[s1;s2] so_lambda: λ2x.t[x] so_apply: x[s] decidable_functionality iff_preserves_decidability decidable__and decidable__less_than' rless-case: rless-case(x;y;n;z)
Lemmas referenced :  rless-cases-proof lifting-strict-spread has-value_wf_base base_wf is-exception_wf top_wf equal_wf lifting-strict-decide lifting-strict-less rless-iff8 decidable__lt decidable__squash decidable_functionality iff_preserves_decidability decidable__and decidable__less_than'
Rules used in proof :  introduction sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity cut instantiate extract_by_obid hypothesis sqequalRule thin sqequalHypSubstitution isectElimination baseClosed isect_memberEquality voidElimination voidEquality independent_isectElimination independent_pairFormation lambdaFormation callbyvalueApply baseApply closedConclusion hypothesisEquality applyExceptionCases inrFormation imageMemberEquality imageElimination exceptionSqequal inlFormation callbyvalueDecide equalityTransitivity equalitySymmetry unionEquality unionElimination sqleReflexivity dependent_functionElimination independent_functionElimination decideExceptionCases because_Cache

Latex:
\mforall{}x,y:\mBbbR{}.    ((x  <  y)  {}\mRightarrow{}  (\mforall{}z:\mBbbR{}.  ((x  <  z)  \mvee{}  (z  <  y))))



Date html generated: 2017_10_03-AM-08_46_36
Last ObjectModification: 2017_07_28-AM-07_32_44

Theory : reals


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