Okay so a Symmetric Random Walk (from a coin toss experiment) is defined as:
$M_k$ = $\sum_{i=0}^k X_j$ , k=1,2,3...
Where $X_j$ takes the values -1 or 1 for Tails and Heads
Then they say that the increments,
$M_{k_1}$ = ($M_{k_1}$ - $M_{k_0}$), ($M_{k_2}$ - $M_{k_1}$), .... ($M_{k_m}$ - $M_{k_{m-1}}$)
are independent.
Stupid question, but I just want to clarify what $k_1$, $k_2$, $k_3$... are. Are the equal increments of k? i.e if $k_1$ is 3, then $k_2$ is 4 and so on? Or is it something else?