Description: The transitive closure function. (Contributed by Mario Carneiro, 23-Jun-2013)
Ref | Expression | ||
---|---|---|---|
Assertion | df-tc | ⊢ TC = ( 𝑥 ∈ V ↦ ∩ { 𝑦 ∣ ( 𝑥 ⊆ 𝑦 ∧ Tr 𝑦 ) } ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
0 | ctc | ⊢ TC | |
1 | vx | ⊢ 𝑥 | |
2 | cvv | ⊢ V | |
3 | vy | ⊢ 𝑦 | |
4 | 1 | cv | ⊢ 𝑥 |
5 | 3 | cv | ⊢ 𝑦 |
6 | 4 5 | wss | ⊢ 𝑥 ⊆ 𝑦 |
7 | 5 | wtr | ⊢ Tr 𝑦 |
8 | 6 7 | wa | ⊢ ( 𝑥 ⊆ 𝑦 ∧ Tr 𝑦 ) |
9 | 8 3 | cab | ⊢ { 𝑦 ∣ ( 𝑥 ⊆ 𝑦 ∧ Tr 𝑦 ) } |
10 | 9 | cint | ⊢ ∩ { 𝑦 ∣ ( 𝑥 ⊆ 𝑦 ∧ Tr 𝑦 ) } |
11 | 1 2 10 | cmpt | ⊢ ( 𝑥 ∈ V ↦ ∩ { 𝑦 ∣ ( 𝑥 ⊆ 𝑦 ∧ Tr 𝑦 ) } ) |
12 | 0 11 | wceq | ⊢ TC = ( 𝑥 ∈ V ↦ ∩ { 𝑦 ∣ ( 𝑥 ⊆ 𝑦 ∧ Tr 𝑦 ) } ) |