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Definition df-ushgr 28900
Description: Define the class of all undirected simple hypergraphs. An undirected simple hypergraph is a special (non-simple, multiple, multi-) hypergraph for which the edge function 𝑒 is an injective (one-to-one) function into subsets of the set of vertices 𝑣, representing the (one or more) vertices incident to the edge. This definition corresponds to the definition of hypergraphs in section I.1 of [Bollobas] p. 7 (except that the empty set seems to be allowed to be an "edge") or section 1.10 of [Diestel] p. 27, where "E is a subset of [...] the power set of V, that is the set of all subsets of V" resp. "the elements of E are nonempty subsets (of any cardinality) of V". (Contributed by AV, 19-Jan-2020.) (Revised by AV, 8-Oct-2020.)
Assertion
Ref Expression
df-ushgr USHGraph = {𝑔[(Vtx‘𝑔) / 𝑣][(iEdg‘𝑔) / 𝑒]𝑒:dom 𝑒1-1→(𝒫 𝑣 ∖ {∅})}
Distinct variable group:   𝑒,𝑔,𝑣

Detailed syntax breakdown of Definition df-ushgr
StepHypRef Expression
1 cushgr 28898 . 2 class USHGraph
2 ve . . . . . . . 8 setvar 𝑒
32cv 1532 . . . . . . 7 class 𝑒
43cdm 5682 . . . . . 6 class dom 𝑒
5 vv . . . . . . . . 9 setvar 𝑣
65cv 1532 . . . . . . . 8 class 𝑣
76cpw 4606 . . . . . . 7 class 𝒫 𝑣
8 c0 4326 . . . . . . . 8 class
98csn 4632 . . . . . . 7 class {∅}
107, 9cdif 3946 . . . . . 6 class (𝒫 𝑣 ∖ {∅})
114, 10, 3wf1 6550 . . . . 5 wff 𝑒:dom 𝑒1-1→(𝒫 𝑣 ∖ {∅})
12 vg . . . . . . 7 setvar 𝑔
1312cv 1532 . . . . . 6 class 𝑔
14 ciedg 28838 . . . . . 6 class iEdg
1513, 14cfv 6553 . . . . 5 class (iEdg‘𝑔)
1611, 2, 15wsbc 3778 . . . 4 wff [(iEdg‘𝑔) / 𝑒]𝑒:dom 𝑒1-1→(𝒫 𝑣 ∖ {∅})
17 cvtx 28837 . . . . 5 class Vtx
1813, 17cfv 6553 . . . 4 class (Vtx‘𝑔)
1916, 5, 18wsbc 3778 . . 3 wff [(Vtx‘𝑔) / 𝑣][(iEdg‘𝑔) / 𝑒]𝑒:dom 𝑒1-1→(𝒫 𝑣 ∖ {∅})
2019, 12cab 2705 . 2 class {𝑔[(Vtx‘𝑔) / 𝑣][(iEdg‘𝑔) / 𝑒]𝑒:dom 𝑒1-1→(𝒫 𝑣 ∖ {∅})}
211, 20wceq 1533 1 wff USHGraph = {𝑔[(Vtx‘𝑔) / 𝑣][(iEdg‘𝑔) / 𝑒]𝑒:dom 𝑒1-1→(𝒫 𝑣 ∖ {∅})}
Colors of variables: wff setvar class
This definition is referenced by:  isushgr  28902
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