A path composed of connected horizontal and vertical line segments, each passing between adjacent lattice points. A lattice path is therefore a sequence of points P_0, P_1, ..., P_n with n>=0 such that each P_i is a lattice point and P_(i + 1) is obtained by offsetting one unit east (or west) or one unit north (or south). The number of paths of length a + b from the origin (0, 0) to a point (a, b) which are restricted to east and north steps is given by the binomial coefficient (a + b a).

ballot problem | Dyck path | Faber polynomial | golygon | kings problem | lattice point | p-good path | random walk | staircase walk