Nuprl Lemma : m-open-set
∀[X:Type]. ∀[d:metric(X)]. ∀[A:X ⟶ ℙ].  (m-open(X;d;x.A[x]) ⇒ m-set(X;d;x.A[x]))
Proof
Definitions occuring in Statement : 
m-set: m-set(X;d;x.A[x]), 
m-open: m-open(X;d;x.A[x]), 
metric: metric(X), 
uall: ∀[x:A]. B[x], 
prop: ℙ, 
so_apply: x[s], 
implies: P ⇒ Q, 
function: x:A ⟶ B[x], 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
implies: P ⇒ Q, 
m-open: m-open(X;d;x.A[x]), 
m-set: m-set(X;d;x.A[x]), 
all: ∀x:A. B[x], 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
member: t ∈ T, 
exists: ∃x:A. B[x], 
so_apply: x[s], 
subtype_rel: A ⊆r B, 
prop: ℙ, 
rev_implies: P ⇐ Q, 
so_lambda: λ2x.t[x], 
nat_plus: ℕ+, 
uimplies: b supposing a, 
not: ¬A, 
satisfiable_int_formula: satisfiable_int_formula(fmla), 
false: False, 
uiff: uiff(P;Q), 
decidable: Dec(P), 
or: P ∨ Q, 
rev_uimplies: rev_uimplies(P;Q)
Latex:
\mforall{}[X:Type].  \mforall{}[d:metric(X)].  \mforall{}[A:X  {}\mrightarrow{}  \mBbbP{}].    (m-open(X;d;x.A[x])  {}\mRightarrow{}  m-set(X;d;x.A[x]))
Date html generated:
2020_05_20-AM-11_55_13
Last ObjectModification:
2020_01_12-PM-00_36_38
Theory : reals
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