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Description: We can always find values matching x and y , as long as they are represented by distinct variables. Version of 2ax6elem with a distinct variable constraint. Usage of this theorem is discouraged because it depends on ax-13 . (Contributed by Wolf Lammen, 28-Sep-2018) (Proof shortened by Wolf Lammen, 3-Oct-2023) (New usage is discouraged.)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | 2ax6e | ⊢ ∃ 𝑧 ∃ 𝑤 ( 𝑧 = 𝑥 ∧ 𝑤 = 𝑦 ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | aeveq | ⊢ ( ∀ 𝑤 𝑤 = 𝑧 → 𝑧 = 𝑥 ) | |
| 2 | aeveq | ⊢ ( ∀ 𝑤 𝑤 = 𝑧 → 𝑤 = 𝑦 ) | |
| 3 | 1 2 | jca | ⊢ ( ∀ 𝑤 𝑤 = 𝑧 → ( 𝑧 = 𝑥 ∧ 𝑤 = 𝑦 ) ) |
| 4 | 3 | 19.8ad | ⊢ ( ∀ 𝑤 𝑤 = 𝑧 → ∃ 𝑤 ( 𝑧 = 𝑥 ∧ 𝑤 = 𝑦 ) ) |
| 5 | 4 | 19.8ad | ⊢ ( ∀ 𝑤 𝑤 = 𝑧 → ∃ 𝑧 ∃ 𝑤 ( 𝑧 = 𝑥 ∧ 𝑤 = 𝑦 ) ) |
| 6 | 2ax6elem | ⊢ ( ¬ ∀ 𝑤 𝑤 = 𝑧 → ∃ 𝑧 ∃ 𝑤 ( 𝑧 = 𝑥 ∧ 𝑤 = 𝑦 ) ) | |
| 7 | 5 6 | pm2.61i | ⊢ ∃ 𝑧 ∃ 𝑤 ( 𝑧 = 𝑥 ∧ 𝑤 = 𝑦 ) |