Description: Proof of cnegex2 without ax-mulcom . (Contributed by SN, 5-May-2024)
Ref | Expression | ||
---|---|---|---|
Assertion | sn-negex2 | ⊢ ( 𝐴 ∈ ℂ → ∃ 𝑏 ∈ ℂ ( 𝑏 + 𝐴 ) = 0 ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | sn-negex12 | ⊢ ( 𝐴 ∈ ℂ → ∃ 𝑏 ∈ ℂ ( ( 𝐴 + 𝑏 ) = 0 ∧ ( 𝑏 + 𝐴 ) = 0 ) ) | |
2 | simpr | ⊢ ( ( ( 𝐴 + 𝑏 ) = 0 ∧ ( 𝑏 + 𝐴 ) = 0 ) → ( 𝑏 + 𝐴 ) = 0 ) | |
3 | 2 | reximi | ⊢ ( ∃ 𝑏 ∈ ℂ ( ( 𝐴 + 𝑏 ) = 0 ∧ ( 𝑏 + 𝐴 ) = 0 ) → ∃ 𝑏 ∈ ℂ ( 𝑏 + 𝐴 ) = 0 ) |
4 | 1 3 | syl | ⊢ ( 𝐴 ∈ ℂ → ∃ 𝑏 ∈ ℂ ( 𝑏 + 𝐴 ) = 0 ) |