Question: Who was born earlier, Robert Bunsen or Gustav Kirchhoff?
Sentence (from "Kirchhoff's theorem"): In the mathematical field of graph theory, Kirchhoff's theorem or Kirchhoff's matrix tree theorem named after Gustav Kirchhoff is a theorem about the number of spanning trees in a graph, showing that this number can be computed in polynomial time as the determinant of a matrix derived from the graph.
Relevant evidence: No