Step
*
of Lemma
cantor-middle-third-lemma
∀x,a,b:ℝ. ((x ∈ [(2 * a + b)/3, b]) ∨ (x ∈ [a, (a + 2 * b)/3])) supposing ((x ∈ [a, b]) and (a < b))
BY
{ (Auto
THEN RepUR ``i-member`` -1
THEN RepUR ``i-member`` 0
THEN (InstLemma `rless-cases` [⌜(2 * a + b)/3⌝;⌜(a + 2 * b)/3⌝;⌜x⌝]⋅ THENM ParallelLast)
THEN Auto) }
1
.....antecedent.....
1. x : ℝ
2. a : ℝ
3. b : ℝ
4. [%] : a < b
5. [%1] : (a ≤ x) ∧ (x ≤ b)
⊢ (2 * a + b)/3 < (a + 2 * b)/3
2
1. x : ℝ
2. a : ℝ
3. b : ℝ
4. [%] : a < b
5. [%1] : (a ≤ x) ∧ (x ≤ b)
6. (2 * a + b)/3 < x
7. (2 * a + b)/3 ≤ x
⊢ x ≤ b
3
1. x : ℝ
2. a : ℝ
3. b : ℝ
4. [%] : a < b
5. [%1] : (a ≤ x) ∧ (x ≤ b)
6. x < (a + 2 * b)/3
⊢ a ≤ x
Latex:
Latex:
\mforall{}x,a,b:\mBbbR{}.
((x \mmember{} [(2 * a + b)/3, b]) \mvee{} (x \mmember{} [a, (a + 2 * b)/3])) supposing ((x \mmember{} [a, b]) and (a < b))
By
Latex:
(Auto
THEN RepUR ``i-member`` -1
THEN RepUR ``i-member`` 0
THEN (InstLemma `rless-cases` [\mkleeneopen{}(2 * a + b)/3\mkleeneclose{};\mkleeneopen{}(a + 2 * b)/3\mkleeneclose{};\mkleeneopen{}x\mkleeneclose{}]\mcdot{} THENM ParallelLast)
THEN Auto)
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