Use a unified representation for all trace types

lean/Spa/Language/Properties.lean

@@ -27,16 +27,6 @@ section Embeddings
 
 variable {g₁ g₂ : Graph} {ρ₁ ρ₂ : Env}
 
-/-- Transport a trace along a graph embedding: an embedding preserves node
-    payloads and edges, which is everything a trace is made of. This is the
-    single induction behind all the per-operator lifting corollaries below. -/
-noncomputable def Trace.embed {g h : Graph} (e : GGraph.Embed g h)
-    {idx₁ idx₂ : g.Index} (tr : Trace g idx₁ idx₂ ρ₁ ρ₂) :
-    Trace h (e.f idx₁) (e.f idx₂) ρ₁ ρ₂ := by
-  induction tr with
-  | single hbs => exact Trace.single (by rwa [e.nodes_eq])
-  | edge hbs he _ ih => exact Trace.edge (by rwa [e.nodes_eq]) (e.edges_mem he) ih
-
 /-- When two graphs are overlaid, for each trace in the left graph,
     a corresponding trace exists in the combined graph. -/
 noncomputable def Trace.overlay_left {idx₁ idx₂ : g₁.Index}