Journal Name: Cognitive Linguistics Issue: Ahead of print.

A pseudo-natural algorithm for the word problem of a finitely presented group is an algorithm which not only tells us whether or not a word w equals 1 in the group but also gives a derivation of 1 from w when w equals 1. In [13], [14] Madlener and Otto show that, if we measure complexity of a primitive recursive algorithm by its level in the Grzegorczyk hierarchy, there are groups in which a pseudo-natural algorithm is arbitrarily more complicated than (...) an algorithm which simply solves the word problem. In a given group the lowest degree of complexity that can be realised by a pseudo-natural algorithm is essentially the derivational complexity of that group. Thus the result separates the derivational complexity of the word problem of a finitely presented group from its intrinsic complexity. The proof given in [13] involves the construction of a finitely presented group G from a Turing machine T such that the intrinsic complexity of the word problem for G reflects the complexity of the halting problem of T, while the derivational complexity of the word problem for G reflects the runtime complexity of T. The proof of one of the crucial lemmas in [13] is only sketched, and part of the purpose of this paper is to give the full details of this proof. We will also obtain a variant of their proof, using modular machines rather than Turing machines. As for several other results, this simplifies the proofs considerably. MSC: 03D40, 20F10. (shrink)

Experimental studies report positive effects of signing for language acquisition and communication in children with and without language development delays. However, little data are available on natural kindergarten settings. Therefore, our study used questionnaire data to investigate the sign learning in hearing children with and without language development delays in an inclusive kindergarten group with a co-enrolled deaf child and a deaf signing educator. We observed that the hearing children in this co-enrollment group learned more signs than the hearing children (...) from groups with only hearing educators who learned signs in a training program. Hearing children’s sign learning showed a tendency toward correlating positively with their level of spoken language development. However, the individual background for children with language development delays impacted this relationship. Additionally, we examined the modality use of all children in interactions with hearing and deaf educators and peers using questionnaire and video data. Despite acquiring signs, hearing children predominantly used spoken language with hearing educators and predominantly nonverbal communication strategies with the deaf educator and the deaf child. Children with language development delays used code-blending with hearing educators in a few cases. The deaf child used mainly sign language for interactions with the deaf educator and mainly nonverbal communication with hearing educators and peers. Overall, our results suggest that the presence of a deaf educator increases sign learning in hearing children. However, in interactions during free play, they barely used signs making it particularly challenging for the deaf child to participate. This reveals that, in addition to a deaf role model, more sign language competent peers and targeted approaches increasing the use of the visual modality are required. (shrink)

Dr Rouner has produced a highly readable and, if one may judge by those whom he had check his facts, W E Hocking and his son Richard Hocking, also a very reliable book. The book is a largely reworked Columbia University doctoral dissertation, originally done under the direction of W Pauck, J H Randall, claimed by the author to be ‘the foremost English-speaking historian of modern Western philosophy’, and M S Bates.

This is a collection of four essays by Tillich emphasizing in various ways the basic point that the future of man must involve the religious dimension and perspective. It includes his last public lecture, "The Significance of the History of Religions for the Systematic Theologian," in which he rejects the reductionism both of orthodoxy, which locates revelation only in its own religion, and of a theology of the secular, which has no room for the sacred. He favors instead a "dynamic-typological" (...) approach to the theology of the history of religions that discovers elements in the experience of the Holy in all religions, whose unity and telos will be in a "Religion of the Concrete Spirit." The three other lectures complement the thrust of this lecture. In "The Decline and Validity of the Idea of Progress," Tillich finds the proper perspective toward history and progress in kairoi, moments of partial but creative fulfillment. In "Frontiers" he speaks of crossing and reversing boundaries as the way to peace. And in "The Effects of Space Exploration on Man's Condition" he notes the emergence of a new ideal of human existence and affirms it doesn't change the divine-human relationship. The book also includes tributes by Jerald C. Brauer, Wilhelm Pauck, and Mircea Eliade, and a set of photographs by Archie Lieberman.--R. G. K. (shrink)