1-2hit |
In this note, we present some results about parses of codes. First we present a sufficient condition of a bifix code to have the bounded indicator. Next we consider a proper parse, introduced notion. We prove that for a strongly infix code, the number of proper parses is at most three under some condition. We also prove that if a code X has a unique proper parse for each word under the same condition, then X is a strongly infix code.
We consider the following three statements for a code L. (P1) For every n 2, both wn Ln and wn+1 Ln+1 imply w L. (P2) For every n 2, if wn Ln, then w L. (P3) For every m, k 2 with m k, wk Lm implies w L. First we show that for every code L, P1 holds. Next we show that for every infix code L, P2 holds, and that a code L is an infix code iff P2 holds and L is a weakly infix code. Last we show that for every strongly infix code L, P3 holds, and that a code L is a strongly infix code iff P3 holds and L is a hyper infix code.