Why the following works only with integers and if other names of vertices are used UndirectedEdge is needed?
{Graph[{{1, 2}, {2, 3}, {3, 1}}], Graph[{{a, b}, {b, c}, {c, a}}],
Graph[UndirectedEdge @@@ {{a, b}, {b, c}, {c, a}}]} // Row
Why the following works only with integers and if other names of vertices are used UndirectedEdge is needed?
{Graph[{{1, 2}, {2, 3}, {3, 1}}], Graph[{{a, b}, {b, c}, {c, a}}],
Graph[UndirectedEdge @@@ {{a, b}, {b, c}, {c, a}}]} // Row