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Database
GRAPH THEORY
Undirected graphs
Undirected pseudographs and multigraphs
umgrunop
Metamath Proof Explorer
Description: The union of two multigraphs (with the same vertex set): If
<. V , E >. and <. V , F >. are multigraphs, then
<. V , E u. F >. is a multigraph (the vertex set stays the same, but
the edges from both graphs are kept). (Contributed by Mario Carneiro , 12-Mar-2015) (Revised by AV , 25-Nov-2020)
Ref
Expression
Hypotheses
umgrun.g
⊢ φ → G ∈ UMGraph
umgrun.h
⊢ φ → H ∈ UMGraph
umgrun.e
⊢ E = iEdg ⁡ G
umgrun.f
⊢ F = iEdg ⁡ H
umgrun.vg
⊢ V = Vtx ⁡ G
umgrun.vh
⊢ φ → Vtx ⁡ H = V
umgrun.i
⊢ φ → dom ⁡ E ∩ dom ⁡ F = ∅
Assertion
umgrunop
⊢ φ → V E ∪ F ∈ UMGraph
Proof
Step
Hyp
Ref
Expression
1
umgrun.g
⊢ φ → G ∈ UMGraph
2
umgrun.h
⊢ φ → H ∈ UMGraph
3
umgrun.e
⊢ E = iEdg ⁡ G
4
umgrun.f
⊢ F = iEdg ⁡ H
5
umgrun.vg
⊢ V = Vtx ⁡ G
6
umgrun.vh
⊢ φ → Vtx ⁡ H = V
7
umgrun.i
⊢ φ → dom ⁡ E ∩ dom ⁡ F = ∅
8
opex
⊢ V E ∪ F ∈ V
9
8
a1i
⊢ φ → V E ∪ F ∈ V
10
5
fvexi
⊢ V ∈ V
11
3
fvexi
⊢ E ∈ V
12
4
fvexi
⊢ F ∈ V
13
11 12
unex
⊢ E ∪ F ∈ V
14
10 13
pm3.2i
⊢ V ∈ V ∧ E ∪ F ∈ V
15
opvtxfv
⊢ V ∈ V ∧ E ∪ F ∈ V → Vtx ⁡ V E ∪ F = V
16
14 15
mp1i
⊢ φ → Vtx ⁡ V E ∪ F = V
17
opiedgfv
⊢ V ∈ V ∧ E ∪ F ∈ V → iEdg ⁡ V E ∪ F = E ∪ F
18
14 17
mp1i
⊢ φ → iEdg ⁡ V E ∪ F = E ∪ F
19
1 2 3 4 5 6 7 9 16 18
umgrun
⊢ φ → V E ∪ F ∈ UMGraph