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Description: Triviality of singleton powers: set equipollence. (Contributed by Stefan O'Rear, 24-Jan-2015)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | pwssnf1o.y | ⊢ 𝑌 = ( 𝑅 ↑s { 𝐼 } ) | |
| pwssnf1o.b | ⊢ 𝐵 = ( Base ‘ 𝑅 ) | ||
| pwssnf1o.f | ⊢ 𝐹 = ( 𝑥 ∈ 𝐵 ↦ ( { 𝐼 } × { 𝑥 } ) ) | ||
| pwssnf1o.c | ⊢ 𝐶 = ( Base ‘ 𝑌 ) | ||
| Assertion | pwssnf1o | ⊢ ( ( 𝑅 ∈ 𝑉 ∧ 𝐼 ∈ 𝑊 ) → 𝐹 : 𝐵 –1-1-onto→ 𝐶 ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | pwssnf1o.y | ⊢ 𝑌 = ( 𝑅 ↑s { 𝐼 } ) | |
| 2 | pwssnf1o.b | ⊢ 𝐵 = ( Base ‘ 𝑅 ) | |
| 3 | pwssnf1o.f | ⊢ 𝐹 = ( 𝑥 ∈ 𝐵 ↦ ( { 𝐼 } × { 𝑥 } ) ) | |
| 4 | pwssnf1o.c | ⊢ 𝐶 = ( Base ‘ 𝑌 ) | |
| 5 | 2 | fvexi | ⊢ 𝐵 ∈ V |
| 6 | simpr | ⊢ ( ( 𝑅 ∈ 𝑉 ∧ 𝐼 ∈ 𝑊 ) → 𝐼 ∈ 𝑊 ) | |
| 7 | 3 | mapsnf1o | ⊢ ( ( 𝐵 ∈ V ∧ 𝐼 ∈ 𝑊 ) → 𝐹 : 𝐵 –1-1-onto→ ( 𝐵 ↑m { 𝐼 } ) ) |
| 8 | 5 6 7 | sylancr | ⊢ ( ( 𝑅 ∈ 𝑉 ∧ 𝐼 ∈ 𝑊 ) → 𝐹 : 𝐵 –1-1-onto→ ( 𝐵 ↑m { 𝐼 } ) ) |
| 9 | snex | ⊢ { 𝐼 } ∈ V | |
| 10 | 1 2 | pwsbas | ⊢ ( ( 𝑅 ∈ 𝑉 ∧ { 𝐼 } ∈ V ) → ( 𝐵 ↑m { 𝐼 } ) = ( Base ‘ 𝑌 ) ) |
| 11 | 9 10 | mpan2 | ⊢ ( 𝑅 ∈ 𝑉 → ( 𝐵 ↑m { 𝐼 } ) = ( Base ‘ 𝑌 ) ) |
| 12 | 11 | adantr | ⊢ ( ( 𝑅 ∈ 𝑉 ∧ 𝐼 ∈ 𝑊 ) → ( 𝐵 ↑m { 𝐼 } ) = ( Base ‘ 𝑌 ) ) |
| 13 | 4 12 | eqtr4id | ⊢ ( ( 𝑅 ∈ 𝑉 ∧ 𝐼 ∈ 𝑊 ) → 𝐶 = ( 𝐵 ↑m { 𝐼 } ) ) |
| 14 | 13 | f1oeq3d | ⊢ ( ( 𝑅 ∈ 𝑉 ∧ 𝐼 ∈ 𝑊 ) → ( 𝐹 : 𝐵 –1-1-onto→ 𝐶 ↔ 𝐹 : 𝐵 –1-1-onto→ ( 𝐵 ↑m { 𝐼 } ) ) ) |
| 15 | 8 14 | mpbird | ⊢ ( ( 𝑅 ∈ 𝑉 ∧ 𝐼 ∈ 𝑊 ) → 𝐹 : 𝐵 –1-1-onto→ 𝐶 ) |