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Description: Lemma 2 for 1pthd . (Contributed by Alexander van der Vekens, 4-Dec-2017) (Revised by AV, 22-Jan-2021)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | 1wlkd.p | ⊢ 𝑃 = 〈“ 𝑋 𝑌 ”〉 | |
| 1wlkd.f | ⊢ 𝐹 = 〈“ 𝐽 ”〉 | ||
| Assertion | 1pthdlem2 | ⊢ ( ( 𝑃 “ { 0 , ( ♯ ‘ 𝐹 ) } ) ∩ ( 𝑃 “ ( 1 ..^ ( ♯ ‘ 𝐹 ) ) ) ) = ∅ |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | 1wlkd.p | ⊢ 𝑃 = 〈“ 𝑋 𝑌 ”〉 | |
| 2 | 1wlkd.f | ⊢ 𝐹 = 〈“ 𝐽 ”〉 | |
| 3 | 2 | fveq2i | ⊢ ( ♯ ‘ 𝐹 ) = ( ♯ ‘ 〈“ 𝐽 ”〉 ) |
| 4 | s1len | ⊢ ( ♯ ‘ 〈“ 𝐽 ”〉 ) = 1 | |
| 5 | 3 4 | eqtri | ⊢ ( ♯ ‘ 𝐹 ) = 1 |
| 6 | 5 | oveq2i | ⊢ ( 1 ..^ ( ♯ ‘ 𝐹 ) ) = ( 1 ..^ 1 ) |
| 7 | fzo0 | ⊢ ( 1 ..^ 1 ) = ∅ | |
| 8 | 6 7 | eqtri | ⊢ ( 1 ..^ ( ♯ ‘ 𝐹 ) ) = ∅ |
| 9 | 8 | imaeq2i | ⊢ ( 𝑃 “ ( 1 ..^ ( ♯ ‘ 𝐹 ) ) ) = ( 𝑃 “ ∅ ) |
| 10 | 9 | ineq2i | ⊢ ( ( 𝑃 “ { 0 , ( ♯ ‘ 𝐹 ) } ) ∩ ( 𝑃 “ ( 1 ..^ ( ♯ ‘ 𝐹 ) ) ) ) = ( ( 𝑃 “ { 0 , ( ♯ ‘ 𝐹 ) } ) ∩ ( 𝑃 “ ∅ ) ) |
| 11 | ima0 | ⊢ ( 𝑃 “ ∅ ) = ∅ | |
| 12 | 11 | ineq2i | ⊢ ( ( 𝑃 “ { 0 , ( ♯ ‘ 𝐹 ) } ) ∩ ( 𝑃 “ ∅ ) ) = ( ( 𝑃 “ { 0 , ( ♯ ‘ 𝐹 ) } ) ∩ ∅ ) |
| 13 | in0 | ⊢ ( ( 𝑃 “ { 0 , ( ♯ ‘ 𝐹 ) } ) ∩ ∅ ) = ∅ | |
| 14 | 12 13 | eqtri | ⊢ ( ( 𝑃 “ { 0 , ( ♯ ‘ 𝐹 ) } ) ∩ ( 𝑃 “ ∅ ) ) = ∅ |
| 15 | 10 14 | eqtri | ⊢ ( ( 𝑃 “ { 0 , ( ♯ ‘ 𝐹 ) } ) ∩ ( 𝑃 “ ( 1 ..^ ( ♯ ‘ 𝐹 ) ) ) ) = ∅ |