Description: The order of a star graph S_N. (Contributed by AV, 12-Sep-2025)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | stgrvtx0.g | |- G = ( StarGr ` N ) |
|
| stgrvtx0.v | |- V = ( Vtx ` G ) |
||
| Assertion | stgrorder | |- ( N e. NN0 -> ( # ` V ) = ( N + 1 ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | stgrvtx0.g | |- G = ( StarGr ` N ) |
|
| 2 | stgrvtx0.v | |- V = ( Vtx ` G ) |
|
| 3 | 1 | fveq2i | |- ( Vtx ` G ) = ( Vtx ` ( StarGr ` N ) ) |
| 4 | 2 3 | eqtri | |- V = ( Vtx ` ( StarGr ` N ) ) |
| 5 | stgrvtx | |- ( N e. NN0 -> ( Vtx ` ( StarGr ` N ) ) = ( 0 ... N ) ) |
|
| 6 | 4 5 | eqtrid | |- ( N e. NN0 -> V = ( 0 ... N ) ) |
| 7 | 6 | fveq2d | |- ( N e. NN0 -> ( # ` V ) = ( # ` ( 0 ... N ) ) ) |
| 8 | hashfz0 | |- ( N e. NN0 -> ( # ` ( 0 ... N ) ) = ( N + 1 ) ) |
|
| 9 | 7 8 | eqtrd | |- ( N e. NN0 -> ( # ` V ) = ( N + 1 ) ) |