Nuprl Lemma : sets-arrow

[C:SmallCategory]. ∀[X:Top].
  (cat-arrow(sets(C; X)) ~ λAa,Bb. let A,a Aa in let B,b Bb in {f:cat-arrow(C) B| f(b) a ∈ (X A)} )


Proof




Definitions occuring in Statement :  sets: sets(C; X) psc-restriction: f(s) functor-ob: ob(F) cat-arrow: cat-arrow(C) small-category: SmallCategory uall: [x:A]. B[x] top: Top set: {x:A| B[x]}  apply: a lambda: λx.A[x] spread: spread def sqequal: t equal: t ∈ T
Definitions unfolded in proof :  uall: [x:A]. B[x] member: t ∈ T small-category: SmallCategory spreadn: spread4 psc-restriction: f(s) sets: sets(C; X) all: x:A. B[x] top: Top presheaf-elements: el(P) mk-cat: mk-cat and: P ∧ Q functor-arrow: arrow(F) pi2: snd(t)
Lemmas referenced :  cat_arrow_triple_lemma op-cat-arrow top_wf small-category_wf
Rules used in proof :  sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity isect_memberFormation introduction cut hypothesisEquality sqequalHypSubstitution setElimination thin rename productElimination sqequalRule extract_by_obid dependent_functionElimination isect_memberEquality voidElimination voidEquality hypothesis equalityTransitivity equalitySymmetry isectElimination sqequalAxiom because_Cache

Latex:
\mforall{}[C:SmallCategory].  \mforall{}[X:Top].
    (cat-arrow(sets(C;  X))  \msim{}  \mlambda{}Aa,Bb.  let  A,a  =  Aa  in  let  B,b  =  Bb  in  \{f:cat-arrow(C)  A  B|  f(b)  =  a\}  )



Date html generated: 2018_05_22-PM-09_59_17
Last ObjectModification: 2018_05_20-PM-09_42_07

Theory : presheaf!models!of!type!theory


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