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People,<BR>
<BR>
Having the goal of m < n → n ∸ m > 0 (for ℕ), <BR>
<BR>
and using Standard library 0.9, I program<BR>
<BR>
lemma : ∀ n → (suc n) ∸ n ≡ 1<BR>
lemma 0 = PE.refl <BR>
lemma (suc n) = lemma n<BR>
<BR>
m<n→n∸m>0 : ∀ {m n} → m < n → n ∸ m > 0<BR>
m<n→n∸m>0 {m} {n} m<n = <BR>
≤begin <BR>
suc 0 ≡≤[ PE.sym $ lemma m ]<BR>
suc m ∸ m ≤[ ∸-mono m<n (≤refl {m} PE.refl) ] <BR>
n ∸ m<BR>
≤end<BR>
<BR>
Here lemma looks like a complication that needs to be avoided.<BR>
Is there possible a shorter implementation for the goal?<BR>
<BR>
Thanks,<BR>
<BR>
------<BR>
Sergei
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