nHalfpace(Arch) A platform of a staircase where the stair turns back in exactly the reverse direction of the lower flight. See Quarterpace.☞ This term and quarterpace are rare or unknown in the United States, platform or landing being used instead.
Century Dictionary and Cyclopedia
nhalfpaceIn architecture, same as foot-pace, 3.
nhalfpaceA landing in a stair which separates two flights of stairs. It differs from quarter-pace in that it crosses the ends of both flights, so that the direction of the stairs is completely changed.
We also need an efﬁcient SQ learning algorithm for halfpaces.
Inverse problems in approximate uniform generation