Description: The slot for the involution function is not the slot for the base set in an extensible structure. Formerly part of proof for ressstarv . (Contributed by AV, 18-Oct-2024)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | starvndxnplusgndx | |- ( *r ` ndx ) =/= ( +g ` ndx ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | 2re | |- 2 e. RR |
|
| 2 | 2lt4 | |- 2 < 4 |
|
| 3 | 1 2 | gtneii | |- 4 =/= 2 |
| 4 | starvndx | |- ( *r ` ndx ) = 4 |
|
| 5 | plusgndx | |- ( +g ` ndx ) = 2 |
|
| 6 | 4 5 | neeq12i | |- ( ( *r ` ndx ) =/= ( +g ` ndx ) <-> 4 =/= 2 ) |
| 7 | 3 6 | mpbir | |- ( *r ` ndx ) =/= ( +g ` ndx ) |