Description: 2 divides an odd number increased by 1. (Contributed by AV, 18-Jun-2020)
Ref | Expression | ||
---|---|---|---|
Assertion | 2dvdsoddp1 | ⊢ ( 𝑍 ∈ Odd → 2 ∥ ( 𝑍 + 1 ) ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | 2ndvdsodd | ⊢ ( 𝑍 ∈ Odd → ¬ 2 ∥ 𝑍 ) | |
2 | oddz | ⊢ ( 𝑍 ∈ Odd → 𝑍 ∈ ℤ ) | |
3 | oddp1even | ⊢ ( 𝑍 ∈ ℤ → ( ¬ 2 ∥ 𝑍 ↔ 2 ∥ ( 𝑍 + 1 ) ) ) | |
4 | 2 3 | syl | ⊢ ( 𝑍 ∈ Odd → ( ¬ 2 ∥ 𝑍 ↔ 2 ∥ ( 𝑍 + 1 ) ) ) |
5 | 1 4 | mpbid | ⊢ ( 𝑍 ∈ Odd → 2 ∥ ( 𝑍 + 1 ) ) |