### Nuprl Lemma : length-map

`∀[f:Top]. ∀[T:Type]. ∀[L:T List].  (||map(f;L)|| ~ ||L||)`

Proof

Definitions occuring in Statement :  length: `||as||` map: `map(f;as)` list: `T List` uall: `∀[x:A]. B[x]` top: `Top` universe: `Type` sqequal: `s ~ t`
Definitions unfolded in proof :  uall: `∀[x:A]. B[x]` member: `t ∈ T` all: `∀x:A. B[x]` nat: `ℕ` implies: `P `` Q` false: `False` ge: `i ≥ j ` guard: `{T}` uimplies: `b supposing a` prop: `ℙ` subtype_rel: `A ⊆r B` or: `P ∨ Q` top: `Top` cons: `[a / b]` colength: `colength(L)` so_lambda: `λ2x y.t[x; y]` so_apply: `x[s1;s2]` squash: `↓T` sq_stable: `SqStable(P)` uiff: `uiff(P;Q)` and: `P ∧ Q` le: `A ≤ B` not: `¬A` less_than': `less_than'(a;b)` true: `True` decidable: `Dec(P)` iff: `P `⇐⇒` Q` rev_implies: `P `` Q` subtract: `n - m` nil: `[]` it: `⋅` so_lambda: `λ2x.t[x]` so_apply: `x[s]` sq_type: `SQType(T)` less_than: `a < b`
Rules used in proof :  sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity isect_memberFormation introduction cut thin lambdaFormation extract_by_obid sqequalHypSubstitution isectElimination hypothesisEquality hypothesis setElimination rename intWeakElimination natural_numberEquality independent_isectElimination independent_functionElimination voidElimination sqequalRule lambdaEquality dependent_functionElimination sqequalAxiom cumulativity applyEquality because_Cache unionElimination isect_memberEquality voidEquality promote_hyp hypothesis_subsumption productElimination applyLambdaEquality imageMemberEquality baseClosed imageElimination addEquality dependent_set_memberEquality independent_pairFormation minusEquality equalityTransitivity equalitySymmetry intEquality instantiate universeEquality

Latex:
\mforall{}[f:Top].  \mforall{}[T:Type].  \mforall{}[L:T  List].    (||map(f;L)||  \msim{}  ||L||)

Date html generated: 2017_04_14-AM-08_35_51
Last ObjectModification: 2017_02_27-PM-03_28_03

Theory : list_0

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