Wigner's friend and continuous time evolution of the state of a closed system and the probabilistic, discontinuous collapse of the state of a system upon measurement. Wigner's friend is therefore directly linked to the measurement problem in quantum mechanics with its famous Schrödinger's cat paradox. The thought experiment posits a friend of Wigner in a laboratory and lets him perform a quantum measurement on a physical system (this could be a spin system or also Schrödinger's cat). This system is assumed to be in a superposition of two distinct states, say, state 0 and state 1 (or "dead" and "alive", in the
Dead or Alive Ultimate game mechanics, new game content, online multiplayer capabilities, and the inclusion of Hitomi as a playable character. "Dead or Alive Ultimate" is a compilation game that includes a remade version of "Dead or Alive 2", with re-developed graphics and new stages for the Xbox gaming system. It also includes the original Sega Saturn version of the first "Dead or Alive", with smoothed graphics, but lacks the additional content received in the later-released North American PlayStation version (no Bass or Ayane characters or extra costumes). Both editions include online play. "Dead or Alive Ultimate 1" is essentially identical to its original