REMARKS ON THE PHYSICAL STATES AND THE CHIRAL ALGEBRA OF 2D GRAVITY COUPLED TO C LESS-THAN-OR-EQUAL-TO 1 MATTER

Some elaboration is given to the structure of physical states in 2D gr avity coupled to C less-than-or-equal-to 1 matter, and to the chiral a lgebra (w(infinity)) of C(M) = 1 theory which has been found recently, in the continuum approach, by Witten and by Klebanov and Polyakov. It is then shown that the chiral algebra is realized as well in the mini mal models of gravity (C(M) < 1), so that it stands as a general symme try of 2D gravity theories.