Category: Uncategorized

Problem Detail: The basic idea is to have one or more symbol that clearly indicate the end. For example: Non-ambiguous: $ab^*c$ $(a|b)c$ $ab^+c$ $ab?c$ $a(b|c)$ $c(ab)^*ccc$ $acc^*d$ $abc|bcd$ Ambiguous: $abc^*$ $abc^+$ $abc?$ $acc^*$ or $ac^*c$ An alternative definition of a non-ambiguous Read More …

Problem Detail: Maybe I am missing something obvious, but can it be that P = co-NP $subsetneq$ NP or vice versa? My feeling is that there must be some theorem that rules out this possibility. Asked By : aelguindy Answered By : Boris Read More …

Problem Detail: EPAL, the language of even palindromes, is defined as the language generated by the following unambiguous context-free grammar: $S rightarrow a a$ $S rightarrow b b$ $S rightarrow a S a$ $S rightarrow b S b$ EPAL is the Read More …

Problem Detail: Is it not necessary to encode both the uppercase and lowercase letter while encoding a message with the move-to-front transform? From an old computer science course exam, the problem was to encode Matt_ate_the_mat starting with an empty list. Using Read More …

Problem Detail: I would like to learn more about Amdahl’s Law and other similar topics. In what branch of computer science would one place Amdahl’s law? Could someone point me to a textbook or further reading (aside from Wikipedia or other Read More …

Problem Detail: It can be shown that the logical preposition [ :- (~A->A)->A ] is a theorem (always true). I want to know if anybody knows a real life description for the preposition above? I mean an expression in computer, economics, Read More …

Problem Detail: Normal human math notation treats juxtaposition as implied multiplication, e.g., $2x$ means $2$ multiplied by $x$. This does not seem to be a common feature of computer languages, although it was, for example, supposed to be included in the Read More …