Isomorphism Classes for Order 4 Size 3 Simple Graphs

Theorem
There are $3$ equivalence classes for simple graphs of order $4$ and size $3$ under isomorphism:


 * Isomorphism-Classes-Order4-Size3-Simple.png

Proof
The fact that the $3$ graphs given are not isomorphic follows from Vertex Condition for Isomorphic Graphs.

The vertices have degrees as follows:
 * Graph $1$: $2, 2, 1, 1$
 * Graph $2$: $3, 1, 1, 1$
 * Graph $3$: $2, 2, 2, 0$