diff --git a/src/diagrams/diagrams.jl b/src/diagrams/diagrams.jl
index 40415a2..a2c6c7c 100644
--- a/src/diagrams/diagrams.jl
+++ b/src/diagrams/diagrams.jl
@@ -1,4 +1,6 @@
 using Combinatorics
+using QEDprocesses
+using QEDbase
 
 struct FeynmanDiagramDefinition
     n::Int
@@ -35,3 +37,24 @@ end
 function leaves(partition::TopologyPartition)
     return partition.leaves1 + partition.leaves2 + partition.leaves3
 end
+
+
+#
+# Feynman Diagram, tree-level, QED
+#
+
+struct FeynmanDiagram <: AbstractTreeLevelFeynmanDiagram
+    proc::AbstractProcessDefinition
+end
+
+process(diagram::FeynmanDiagram) = d.proc
+
+function virtual_particles(diagram::FeynmanDiagram)
+
+    return NTuple{N,Tuple{QEDbase.AbstractParticleType,BitArray}}()
+end
+
+function vertices(::AbstractTreeLevelFeynmanDiagram)
+
+    return NTuple{N,VertexType}()
+end