Goal:
    G1 : t  G2 : t  sub : full_subgraph G1 G2
  ============================
   (is_true (VSet.subset (V G1) (V G2)))


DEBUG:Going to execute:
apply /VSet.subset_spec ; apply : vertices_sub 
DEBUG LTAC Evaluated term: andP
Level 0: Backtrace:

Cannot apply view andP
Level 0: Backtrace:

Cannot apply view andP
Level 0: Backtrace:

Cannot apply view andP
Level 0: Backtrace:

Failed to progress.