Hint . Without loss of generality, assume that L = L(G), where G = (V,Σ, P, S) is in Chomsky normal form, and let R = L(D), for some DFA D = (Q,Σ, δ, q0, F ). Use a kind of cross-product construction as sketched below. Construct a CFG G2 whose set of nonterminals is Q×N ×Q ∪ {S0}, where S0 is a new nonterminal, and whose productions are of the form: S0 → (q0, S, f), for every f ∈ F ; (p,A, δ(p,...

This chapter gives a brief introduction to quantum mechanics. Quantum mechanics can be thought of roughly as the study of physics on very small length scales, although there are also certain macroscopic systems it directly applies to. The descriptor “quantum” arises because in contrast with classical mechanics, certain quantities take on only discrete values. However, some quantities still take...

As is well known, Huffman’s algorithm is a remarkably simple, and wonderfully illustrative example of how to use the greedy method to design algorithms. However, the Huffman coding problem, which is to find an optimal binary character code (or an optimal binary tree with weighted leaves) is intrinsically technical, and its specification is ill-suited for students with modest mathematical sophis...

Is it possible to create formal proofs of interesting mathematical theorems which are me chanically checked in every detail and yet are readable and even faithful to the best expositions of those results in the literature This paper answers that question positively for theorems about decidable properties of nite automata The exposition is from Hopcroft and Ullman s classic textbook Formal Langu...

Learning statistics is a necessity for dental researchers. Due to daily dental science expansion, dental researchers have to study new papers in recent dental journals to remain up to date. On the other hand, knowing principles of statistics helps better understanding of the articles. Some authors revealed that knowledge of dentists about basic topics of statistics was poor. Therefore, in this ...

سخن سردبیر Editorial مجله دانشگاه علوم پزشکی رفسنجان دوره 20، اردیبهشت 1400، 146-145       درآمدی بر مرورهای نظام‌مند زنده An Introduction to Living Systematic Reviews   محسن رضائیان[1]   M. Rezaeian    تا کنون در سخنان سردبیری مجله دانشگاه، درباره انواع مقالات مروری، مطالب گوناگونی را به رشته‌ تحریر در آورده‌ایم. هدف از نگارش این مقالات، آشنا ساختن خوانندگان و نویسندگان فرهیخته م...

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lots of viruses, in particular rna viruses, have high mutation rates and relatively short generation times. particle stability during infection in nature or in laboratory triggers the evolutionary event toward different mechanisms such as genome segmentation, point mutation and  recombination. the frequency of mutant genomes increase and modify  the previous distribution, which, consequently, l...