Description: Membership of the empty set in an infinite Cartesian product. (Contributed by Steve Rodriguez, 29-Sep-2006)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | 0elixp | |- (/) e. X_ x e. (/) A | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | 0ex | |- (/) e. _V | |
| 2 | 1 | snid |  |-  (/) e. { (/) } | 
| 3 | ixp0x |  |-  X_ x e. (/) A = { (/) } | |
| 4 | 2 3 | eleqtrri | |- (/) e. X_ x e. (/) A |