p : ℕ → Prop
inst✝¹ : DecidablePred p
q : ℕ → Prop
inst✝ : DecidablePred q
n : ℕ
hpq : ∀ (k : ℕ), p k → q k
⊢ card (filter p (range n)) ≤ card (filter q (range n))
p : ℕ → Prop
inst✝¹ : DecidablePred p
q : ℕ → Prop
inst✝ : DecidablePred q
n : ℕ
hpq : ∀ (k : ℕ), p k → q k
⊢ count p n ≤ count q n
simp only [count_eq_card_filter_range]
no goals
p : ℕ → Prop
inst✝¹ : DecidablePred p
q : ℕ → Prop
inst✝ : DecidablePred q
n : ℕ
hpq : ∀ (k : ℕ), p k → q k
⊢ card (filter p (range n)) ≤ card (filter q (range n))
exact card_le_of_subset ((range n).monotone_filter_right hpq)