Step
*
of Lemma
equipollent-multiply
∀a,b:ℕ. ℕa × ℕb ~ ℕa * b
BY
{ (Auto THEN Unfold `equipollent` 0 THEN InstConcl [⌜λp.let x,y = p in (x * b) + y⌝]⋅ THEN Auto') }
1
1. a : ℕ
2. b : ℕ
3. p1 : ℕa
4. p2 : ℤ
5. 0 ≤ p2
6. p2 < b
⊢ (0 - p1 * b) ≤ p2
2
1. a : ℕ
2. b : ℕ
3. p1 : ℕa
4. p2 : ℤ
5. 0 ≤ p2
6. p2 < b
⊢ p2 < (a * b) - p1 * b
3
1. a : ℕ
2. b : ℕ
⊢ Bij(ℕa × ℕb;ℕa * b;λp.let x,y = p
in (x * b) + y)
Latex:
Latex:
\mforall{}a,b:\mBbbN{}. \mBbbN{}a \mtimes{} \mBbbN{}b \msim{} \mBbbN{}a * b
By
Latex:
(Auto THEN Unfold `equipollent` 0 THEN InstConcl [\mkleeneopen{}\mlambda{}p.let x,y = p in (x * b) + y\mkleeneclose{}]\mcdot{} THEN Auto')
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