equiv_induct - proving $equiv cells using temporal induction

yosys> help equiv_induct
equiv_induct [options] [selection]
Uses a version of temporal induction to prove $equiv cells.

Only selected $equiv cells are proven and only selected cells are used to
perform the proof.
enable modelling of undef states
-seq <N>
the max. number of time steps to be considered (default = 4)
This command is very effective in proving complex sequential circuits, when
the internal state of the circuit quickly propagates to $equiv cells.

However, this command uses a weak definition of 'equivalence': This command
proves that the two circuits will not diverge after they produce equal
outputs (observable points via $equiv) for at least <N> cycles (the <N>
specified via -seq).

Combined with simulation this is very powerful because simulation can give
you confidence that the circuits start out synced for at least <N> cycles
after reset.