Nuprl Lemma : dl-valid-box-choose

∀a,b:Prog. ∀phi:Prop.  |= [a] phi ⇒ [b] phi ⇒ [a ⋃ b] phi


Proof




Definitions occuring in Statement :  dl-valid: |= phi,  dl-box: [x1] x,  dl-implies: x1 ⇒ x,  dl-choose: x1 ⋃ x,  dl-prop: Prop,  dl-prog: Prog,  all: ∀x:A. B[x]
Definitions unfolded in proof :  all: ∀x:A. B[x],  dl-valid: |= phi,  member: t ∈ T,  prop: ℙ,  uall: ∀[x:A]. B[x],  dl-prop-sem: [|phi|],  dl-sem: dl-sem(K;n.R[n];m.P[m]),  so_lambda: λ2x.t[x],  top: Top,  so_apply: x[s],  so_lambda: so_lambda(x,y,z,w.t[x; y; z; w]),  so_apply: x[s1;s2;s3;s4],  so_lambda: λ2x y.t[x; y],  so_apply: x[s1;s2],  dl-prog-sem: [|alpha|],  implies: P ⇒ Q,  or: P ∨ Q,  subtype_rel: A ⊆r B,  guard: {T}
Lemmas referenced :  istype-atom,  istype-universe,  istype-void,  dl-prog-sem_wf,  subtype_rel_self,  dl-prop-sem_wf
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  lambdaFormation_alt,  universeIsType,  hypothesisEquality,  functionIsType,  cut,  introduction,  extract_by_obid,  hypothesis,  universeEquality,  because_Cache,  thin,  instantiate,  sqequalHypSubstitution,  isectElimination,  inhabitedIsType,  sqequalRule,  isect_memberEquality_alt,  voidElimination,  unionElimination,  unionIsType,  applyEquality,  lambdaEquality_alt,  dependent_functionElimination,  independent_functionElimination

Latex:
\mforall{}a,b:Prog.  \mforall{}phi:Prop.    |=  [a]  phi  {}\mRightarrow{}  [b]  phi  {}\mRightarrow{}  [a  \mcup{}  b]  phi



Date html generated: 2019_10_15-AM-11_44_20
Last ObjectModification: 2019_03_26-AM-11_28_30

Theory : dynamic!logic


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