# Question: let g be a simple graph an induced subgraph sg...

###### Question details

Let πΊG be a (simple) graph. An *induced subgraph* πβπΊSβG
is a subgraph such that for all π₯,π¦βπ(π)x,yβV(S) such that
{π₯,π¦}βπΈ(πΊ){x,y}βE(G), then {π₯,π¦}βπΈ(π){x,y}βE(S) (that is to say, it
can be considered as subgraphs of πΊG obtained by deleting
vertices). Let πΎπKndenote the complete graph on πn vertices.

How many induced subgraphs of πΎπKn are there (up to
isomorphism):