On some context free languages that are not deterministic ETOL languages

Ehrenfeucht, Andrzej; Rozenberg, Grzegorz

doi:10.1051/ita/1977110402731

Cited by 32 publications

(19 citation statements)

References 14 publications

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“…[27]). Since DCS is closed under homomorphism it follows that CF _C DCS C EDTOL, which clearly contradicts the incomparability of CF and EDTOL shown in [7]. Hence CF is not included m CS.…”

Section: Deterministic Restrictwnsmentioning

confidence: 62%

Stack Machines and Classes of Nonnested Macro Languages

Engelfriet

Schmidt

Leeuwen

1980

J. ACM

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AnSTV.ACT. A new class of generalized one-way stack automata, called s-pd machines, is mvestlgated The machines are obtained by augmenting a stack automaton with a pushdown store, whose bottom is attached to the top of the stack and whose top follows the movements of the stack-pointer into the stack. Motivations for the modal include a possible protocol for macro expansion with intermittent parameter evaluatton. The languages recogmzed by these machmes are characterized by a natural class of grammars, vlz, the 91ass of OI macro grammars with set-parameters and nonnested function calls (the "extended basic" or EB macro grammars) If the stack is required to be nonerasing or checking, then a useful machine characterizatton for the ETOL languages is obtained, together with the known characterization of this family by means of extended "linear" basic or [~LB macro grammars. It follows that the nonerasmg one-way stack languages are (strictly) included m ETOL. It is proved that the family of unrestricted one-way stack languages and ETOL are incomparable, as are the general OI macro languages and the yields of ranges of topdown tree transducers. It follows that ETOL is strictly included m the family of EB macro languages (which, m turn, is strxctly included in the famdy of indexed languages) Certain determuustic restrictions of s-pd machines lead to machine models for famlhes of nonextended macro languages, vlz, for Ftscher's original linear basic macro (i e, EDTOL) and basle macro languages.

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“…[27]). Since DCS is closed under homomorphism it follows that CF _C DCS C EDTOL, which clearly contradicts the incomparability of CF and EDTOL shown in [7]. Hence CF is not included m CS.…”

Section: Deterministic Restrictwnsmentioning

confidence: 62%

Stack Machines and Classes of Nonnested Macro Languages

Engelfriet

Schmidt

Leeuwen

1980

J. ACM

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“…Following [4], there are context-free languages which are not in $£ (EDTOL). Thus there are context-free languages which do not belong to M f as well.…”

Section: Consequences Of a Results Of Ehrenfeucht And Rozenberg 121mentioning

confidence: 99%

“…Consequently, any context-free generator (any context-free language whose smallest AFL containing it equals the family of context-free languages) is not a matrix language of finite index. Any language D it i ^ 2, is a context-free generator (see example 5.1.1, p. 139 [5] Some problems settled by the resuit in [4] were considered in [4] too. Perhaps there are other problems which can be solved using the same resuit.…”

Section: Consequences Of a Results Of Ehrenfeucht And Rozenberg 121mentioning

confidence: 99%

Some consequences of a result of Ehrenfeucht and Rozenberg

Păun¹

1980

RAIRO. Inform. théor.

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“…The implication from (ii) to (i) immediately follows from m-MCFL(1) = m-MCFL wn (1). To show that (i) implies (ii), suppose that L = L(G) for some G = (N, Σ ∪ {#}, P, S) ∈ m-MCFG wn (2). If L is finite, L clearly belongs to 1-MCFL(1), so we assume that L is infinite.…”

Section: The Double Copying Theorem For Well-nested Multiple Context-mentioning

confidence: 99%

“…2 , the one-sided Dyck language over two pairs of parentheses [2,3] and D * 1 , the one-sided Dyck language over a single pair of parentheses [15]. A question that immediately arises is the status of the "double copying theorem" for OI: when is L = { w#w | w ∈ L 0 } in OI?…”

Section: Introductionmentioning

confidence: 99%