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Description: If a nonnegative integer is an element of a half-open range of nonnegative integers, increasing this integer by one results in an element of a half- open range of nonnegative integers with the upper bound increased by one. (Contributed by Alexander van der Vekens, 5-Aug-2018)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | fzonn0p1p1 | ⊢ ( 𝐼 ∈ ( 0 ..^ 𝑁 ) → ( 𝐼 + 1 ) ∈ ( 0 ..^ ( 𝑁 + 1 ) ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | elfzo0 | ⊢ ( 𝐼 ∈ ( 0 ..^ 𝑁 ) ↔ ( 𝐼 ∈ ℕ0 ∧ 𝑁 ∈ ℕ ∧ 𝐼 < 𝑁 ) ) | |
| 2 | peano2nn0 | ⊢ ( 𝐼 ∈ ℕ0 → ( 𝐼 + 1 ) ∈ ℕ0 ) | |
| 3 | 2 | 3ad2ant1 | ⊢ ( ( 𝐼 ∈ ℕ0 ∧ 𝑁 ∈ ℕ ∧ 𝐼 < 𝑁 ) → ( 𝐼 + 1 ) ∈ ℕ0 ) |
| 4 | peano2nn | ⊢ ( 𝑁 ∈ ℕ → ( 𝑁 + 1 ) ∈ ℕ ) | |
| 5 | 4 | 3ad2ant2 | ⊢ ( ( 𝐼 ∈ ℕ0 ∧ 𝑁 ∈ ℕ ∧ 𝐼 < 𝑁 ) → ( 𝑁 + 1 ) ∈ ℕ ) |
| 6 | simp3 | ⊢ ( ( 𝐼 ∈ ℕ0 ∧ 𝑁 ∈ ℕ ∧ 𝐼 < 𝑁 ) → 𝐼 < 𝑁 ) | |
| 7 | nn0re | ⊢ ( 𝐼 ∈ ℕ0 → 𝐼 ∈ ℝ ) | |
| 8 | nnre | ⊢ ( 𝑁 ∈ ℕ → 𝑁 ∈ ℝ ) | |
| 9 | 1red | ⊢ ( 𝐼 < 𝑁 → 1 ∈ ℝ ) | |
| 10 | ltadd1 | ⊢ ( ( 𝐼 ∈ ℝ ∧ 𝑁 ∈ ℝ ∧ 1 ∈ ℝ ) → ( 𝐼 < 𝑁 ↔ ( 𝐼 + 1 ) < ( 𝑁 + 1 ) ) ) | |
| 11 | 7 8 9 10 | syl3an | ⊢ ( ( 𝐼 ∈ ℕ0 ∧ 𝑁 ∈ ℕ ∧ 𝐼 < 𝑁 ) → ( 𝐼 < 𝑁 ↔ ( 𝐼 + 1 ) < ( 𝑁 + 1 ) ) ) |
| 12 | 6 11 | mpbid | ⊢ ( ( 𝐼 ∈ ℕ0 ∧ 𝑁 ∈ ℕ ∧ 𝐼 < 𝑁 ) → ( 𝐼 + 1 ) < ( 𝑁 + 1 ) ) |
| 13 | elfzo0 | ⊢ ( ( 𝐼 + 1 ) ∈ ( 0 ..^ ( 𝑁 + 1 ) ) ↔ ( ( 𝐼 + 1 ) ∈ ℕ0 ∧ ( 𝑁 + 1 ) ∈ ℕ ∧ ( 𝐼 + 1 ) < ( 𝑁 + 1 ) ) ) | |
| 14 | 3 5 12 13 | syl3anbrc | ⊢ ( ( 𝐼 ∈ ℕ0 ∧ 𝑁 ∈ ℕ ∧ 𝐼 < 𝑁 ) → ( 𝐼 + 1 ) ∈ ( 0 ..^ ( 𝑁 + 1 ) ) ) |
| 15 | 1 14 | sylbi | ⊢ ( 𝐼 ∈ ( 0 ..^ 𝑁 ) → ( 𝐼 + 1 ) ∈ ( 0 ..^ ( 𝑁 + 1 ) ) ) |