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Time Complexity

Another advantage of parsing schemata is that formal results on time complexity can be obtained easily. The time-complexity of the algorithms can directly be derived from the number of relevant indices, where each vector tex2html_wrap_inline10555 represents h indices.

  theorem3461

For a complete discussion of the proof on theorem 4.9, see [Nederhof,1997a]. Note that only those index variables are relevant, that occur in at least two different positions. For example, step tex2html_wrap_inline7919 in algorithm tex2html_wrap_inline10561 has three relevant vectors tex2html_wrap_inline10563 which each represent h indices, resulting in a time-complexity of tex2html_wrap_inline10567 . The Step tex2html_wrap_inline7921 has a tex2html_wrap_inline10571 time-complexity. Since this is the maximum for all deduction steps, the following corollary holds:

corollar23477

The time complexity analysis of tex2html_wrap_inline10577 and tex2html_wrap_inline10579 is carried out in [Becker,Heckmann,2000]. The following upper time-bounds are received:

corollar23485

corollar23490

Finally, the proofs of correctness, that are directly analogous to the CFG cases and can be found in [Becker,Heckmann,2000]

In the first section of this chapter, the parsing schemata for CFG, according to [Sikkel,Nijhold,1997], were introduced and defined elaborately in order to offer a complete overview of this formalism. In the second and third section more than fifteen newly created parsing schemata are defined precisely.

In the following chapter, several formal aspects and applications of recursive matrix systems are discussed. In chapter 6, parsing is revisited form the implementation point of view.



Dominik Heckmann
Tue Feb 29 17:25:02 MET 2000