Definition df-sgra 10653

Description: Define the class of all simple graphs (pseudographs whose edges connect exactly two vertices each). Definition in [Diestel] p. 2, which simply calls them "graphs".

Assertion

Ref	Expression
df-sgra	|- SmpGrph = {<.a, b>. | ((a i^i b) = (/) /\ b (_ (a ^m 2o))}

Distinct variable group:   a,b

Detailed syntax breakdown of Definition df-sgra

Step	Hyp	Ref	Expression
1		csgra 10652	. 2 class SmpGrph
2		va	. . . . . . 7 set a
3	2	cv 953	. . . . . 6 class a
4		vb	. . . . . . 7 set b
5	4	cv 953	. . . . . 6 class b
6	3, 5	cin 2042	. . . . 5 class (a i^i b)
7		c0 2276	. . . . 5 class (/)
8	6, 7	wceq 954	. . . 4 wff (a i^i b) = (/)
9		c2o 4119	. . . . . 6 class 2o
10		cm 4312	. . . . . 6 class ^m
11	3, 9, 10	co 3954	. . . . 5 class (a ^m 2o)
12	5, 11	wss 2043	. . . 4 wff b (_ (a ^m 2o)
13	8, 12	wa 223	. . 3 wff ((a i^i b) = (/) /\ b (_ (a ^m 2o))
14	13, 2, 4	copab 2661	. 2 class {<.a, b>. | ((a i^i b) = (/) /\ b (_ (a ^m 2o))}
15	1, 14	wceq 954	1 wff SmpGrph = {<.a, b>. | ((a i^i b) = (/) /\ b (_ (a ^m 2o))}

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