集合等号自反性
theorem eqs_refl (x: set): $ x = x $;
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | fo_imp_inslsto_ex_absrs | \fo y (y = x \imp x = x) \imp \ex y y = x \imp x = x |
|
| 2 | imp_imp_assiml | (y = x \imp y = x \imp x = x) \imp y = x \imp x = x |
|
| 3 | equality | y = x \imp y = x \imp x = x |
|
| 4 | 2, 3 | ax_mp | y = x \imp x = x |
| 5 | 4 | intro_fo | \fo y (y = x \imp x = x) |
| 6 | 1, 5 | ax_mp | \ex y y = x \imp x = x |
| 7 | existene | \ex y y = x |
|
| 8 | 6, 7 | ax_mp | x = x |