Quasi-perfect_equilibrium
Quasi-perfect equilibrium is a refinement of Nash Equilibrium for extensive form games due to Eric van Damme.[1]
Informally, a player playing by a strategy from a quasi-perfect equilibrium takes observed as well as potential future mistakes of his opponents into account but assumes that he himself will not make a mistake in the future, even if he observes that he has done so in the past.
Quasi-perfect equilibrium is a further refinement of sequential equilibrium. It is itself refined by normal form proper equilibrium.