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SUPPLEMENTARY MATERIAL (USERS' MATHBOXES)
Mathbox for Richard Penner
Short Studies
RP ADDTO: Relations
brnonrel
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dmnonrel
Metamath Proof Explorer
Ascii
Unicode
Theorem
brnonrel
Description:
A non-relation cannot relate any two classes.
(Contributed by
RP
, 23-Oct-2020)
Ref
Expression
Assertion
brnonrel
⊢
X
∈
U
∧
Y
∈
V
→
¬
X
A
∖
A
-1
-1
Y
Proof
Step
Hyp
Ref
Expression
1
br0
⊢
¬
Y
∅
X
2
brcnvg
⊢
Y
∈
V
∧
X
∈
U
→
Y
A
∖
A
-1
-1
-1
X
↔
X
A
∖
A
-1
-1
Y
3
2
ancoms
⊢
X
∈
U
∧
Y
∈
V
→
Y
A
∖
A
-1
-1
-1
X
↔
X
A
∖
A
-1
-1
Y
4
cnvnonrel
⊢
A
∖
A
-1
-1
-1
=
∅
5
4
breqi
⊢
Y
A
∖
A
-1
-1
-1
X
↔
Y
∅
X
6
3
5
bitr3di
⊢
X
∈
U
∧
Y
∈
V
→
X
A
∖
A
-1
-1
Y
↔
Y
∅
X
7
1
6
mtbiri
⊢
X
∈
U
∧
Y
∈
V
→
¬
X
A
∖
A
-1
-1
Y