Nuprl Lemma : range_inf_functionality
∀I:{I:Interval| icompact(I)} . ∀f:{x:ℝ| x ∈ I}  ⟶ ℝ.
  ∀g:{x:ℝ| x ∈ I}  ⟶ ℝ. inf{f[x] | x ∈ I} = inf{g[x] | x ∈ I} supposing ∀x:{x:ℝ| x ∈ I} . (f[x] = g[x]) 
  supposing ∀x,y:{x:ℝ| x ∈ I} .  ((x = y) ⇒ (f[x] = f[y]))
Proof
Definitions occuring in Statement : 
range_inf: inf{f[x] | x ∈ I}, 
icompact: icompact(I), 
i-member: r ∈ I, 
interval: Interval, 
req: x = y, 
real: ℝ, 
uimplies: b supposing a, 
so_apply: x[s], 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
set: {x:A| B[x]} , 
function: x:A ⟶ B[x]
Definitions unfolded in proof : 
all: ∀x:A. B[x], 
uimplies: b supposing a, 
implies: P ⇒ Q, 
member: t ∈ T, 
and: P ∧ Q, 
cand: A c∧ B, 
uall: ∀[x:A]. B[x], 
so_apply: x[s], 
uiff: uiff(P;Q), 
rev_uimplies: rev_uimplies(P;Q), 
guard: {T}, 
prop: ℙ, 
so_lambda: λ2x.t[x], 
inf: inf(A) = b, 
lower-bound: lower-bound(A;b), 
rrange: f[x](x∈I), 
rset-member: x ∈ A, 
exists: ∃x:A. B[x]
Latex:
\mforall{}I:\{I:Interval|  icompact(I)\}  .  \mforall{}f:\{x:\mBbbR{}|  x  \mmember{}  I\}    {}\mrightarrow{}  \mBbbR{}.
    \mforall{}g:\{x:\mBbbR{}|  x  \mmember{}  I\}    {}\mrightarrow{}  \mBbbR{}
        inf\{f[x]  |  x  \mmember{}  I\}  =  inf\{g[x]  |  x  \mmember{}  I\}  supposing  \mforall{}x:\{x:\mBbbR{}|  x  \mmember{}  I\}  .  (f[x]  =  g[x])  
    supposing  \mforall{}x,y:\{x:\mBbbR{}|  x  \mmember{}  I\}  .    ((x  =  y)  {}\mRightarrow{}  (f[x]  =  f[y]))
 Date html generated: 
2020_05_20-PM-00_18_41
 Last ObjectModification: 
2020_01_03-PM-03_04_29
Theory : reals
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