Database
REAL AND COMPLEX NUMBERS
Reflexive and transitive closures of relations
Reflexive-transitive closure as an indexed union
df-rtrclrec
Metamath Proof Explorer
Description: The reflexive, transitive closure of a relation constructed as the union
of all finite exponentiations. (Contributed by Drahflow , 12-Nov-2015)
Ref
Expression
Assertion
df-rtrclrec
⊢ t*rec = r ∈ V ⟼ ⋃ n ∈ ℕ 0 r ↑ r n
Detailed syntax breakdown
Step
Hyp
Ref
Expression
0
crtrcl
class t*rec
1
vr
setvar r
2
cvv
class V
3
vn
setvar n
4
cn0
class ℕ 0
5
1
cv
setvar r
6
crelexp
class ↑ r
7
3
cv
setvar n
8
5 7 6
co
class r ↑ r n
9
3 4 8
ciun
class ⋃ n ∈ ℕ 0 r ↑ r n
10
1 2 9
cmpt
class r ∈ V ⟼ ⋃ n ∈ ℕ 0 r ↑ r n
11
0 10
wceq
wff t*rec = r ∈ V ⟼ ⋃ n ∈ ℕ 0 r ↑ r n