Step
*
of Lemma
int-prod-isolate
∀[n:ℕ]. ∀[m:ℕn]. ∀[f:ℕn ⟶ ℤ]. (Π(f[x] | x < n) = (Π(if (x =z m) then 1 else f[x] fi | x < n) * f[m]) ∈ ℤ)
BY
{ (Auto
THEN ((InstLemma `int-prod-split` [⌜n⌝;⌜f⌝;⌜m⌝]⋅ THENA Auto) THEN HypSubst' (-1) 0 THEN Thin (-1))
THEN (InstLemma `int-prod-split` [⌜n⌝;⌜λ2x.if (x =z m) then 1 else f[x] fi ⌝;⌜m⌝]⋅ THENA Auto)
THEN HypSubst' (-1) 0
THEN Thin (-1)
THEN ((InstLemma `int-prod-split` [⌜n - m⌝;⌜λ2x.f[x + m]⌝;⌜1⌝]⋅ THENA Auto) THEN HypSubst' (-1) 0 THEN Thin (-1))
THEN (InstLemma `int-prod-split` [⌜n - m⌝;⌜λ2x.if (x + m =z m) then 1 else f[x + m] fi ⌝;⌜1⌝]⋅ THENA Auto)
THEN HypSubst' (-1) 0
THEN Thin (-1)) }
1
1. n : ℕ
2. m : ℕn
3. f : ℕn ⟶ ℤ
⊢ (Π(f[x] | x < m) * Π(f[x + m] | x < 1) * Π(f[(x + 1) + m] | x < n - m - 1))
= ((Π(if (x =z m) then 1 else f[x] fi | x < m)
* Π(if (x + m =z m) then 1 else f[x + m] fi | x < 1)
* Π(if ((x + 1) + m =z m) then 1 else f[(x + 1) + m] fi | x < n - m - 1))
* f[m])
∈ ℤ
Latex:
Latex:
\mforall{}[n:\mBbbN{}]. \mforall{}[m:\mBbbN{}n]. \mforall{}[f:\mBbbN{}n {}\mrightarrow{} \mBbbZ{}].
(\mPi{}(f[x] | x < n) = (\mPi{}(if (x =\msubz{} m) then 1 else f[x] fi | x < n) * f[m]))
By
Latex:
(Auto
THEN ((InstLemma `int-prod-split` [\mkleeneopen{}n\mkleeneclose{};\mkleeneopen{}f\mkleeneclose{};\mkleeneopen{}m\mkleeneclose{}]\mcdot{} THENA Auto) THEN HypSubst' (-1) 0 THEN Thin (-1))
THEN (InstLemma `int-prod-split` [\mkleeneopen{}n\mkleeneclose{};\mkleeneopen{}\mlambda{}\msubtwo{}x.if (x =\msubz{} m) then 1 else f[x] fi \mkleeneclose{};\mkleeneopen{}m\mkleeneclose{}]\mcdot{} THENA Auto)
THEN HypSubst' (-1) 0
THEN Thin (-1)
THEN ((InstLemma `int-prod-split` [\mkleeneopen{}n - m\mkleeneclose{};\mkleeneopen{}\mlambda{}\msubtwo{}x.f[x + m]\mkleeneclose{};\mkleeneopen{}1\mkleeneclose{}]\mcdot{} THENA Auto)
THEN HypSubst' (-1) 0
THEN Thin (-1))
THEN (InstLemma `int-prod-split` [\mkleeneopen{}n - m\mkleeneclose{};\mkleeneopen{}\mlambda{}\msubtwo{}x.if (x + m =\msubz{} m) then 1 else f[x + m] fi \mkleeneclose{};\mkleeneopen{}1\mkleeneclose{}]\mcdot{}
THENA Auto
)
THEN HypSubst' (-1) 0
THEN Thin (-1))
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