Problem Detail: A deterministic queue automaton (DQA) is like a PDA except the stack is replaced by a queue. A queue is a tape allowing symbols to be written (push) on the left-end and read (pull) on the right-end. Actually I’ve Read More …
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Show that every infinite language has a non-regular subset
Problem Detail: I’m trying to solve this problem: Let $L$ be some infinite language, show that there exists a sub-language of $L$ that is not regular But can this be correct? If I have the language ${a}^*$ for example, that’s infinite Read More …
Extending the implementation of a Queue using a circular array
Problem Detail: I’m doing some exam (Java-based algorithmics) revision and have been given the question: Describe how you might extend your implementation [of a queue using a circular array] to support the expansion of the Queue to allow it to store Read More …
What’s the difference between a rule based system and an artificial neural network?
Problem Detail: I’m currently doing some reading into AI and up to this point couldn’t find a satisfying answer to this question: what’s the difference between a rule based system and an artificial neural network? From my understanding both are trying Read More …
What does pre-, post- and in-order walk mean for a n-ary tree?
Problem Detail: The tree traversal methods explained in this Wikipedia article are pre-order, post-order and in-order. Are these methods limited to binary trees? The algorithm seems to be defined in terms of left and right child. If it can be used Read More …
Can a RAM calculate its own Gödel number?
Problem Detail: You can get the Gödel number of a RAM by making it a list of commands and making this list an integer. So, what I thought is something like “The RAM that would return its own Gödel number (say, Read More …
Is there a context free, non-regular language $L$, for which $L^*$ is regular?
Problem Detail: I know that there are non-regular languages, so that $L^*$ is regular, but all examples I can find are context-sensitive but not context free. In case there are none how do you prove it? Asked By : Simon S Answered Read More …
What is the height of an empty BST when using it in context for balancing?
Problem Detail: Suppose the datatype for a BST is defined as follows (in SML) datatype ‘a bst_Tree = Empty | Node of (int * ‘a) * ‘a bst_Tree * ‘a bst_Tree; So there are two cases one in which the BST Read More …
Lambda calculus didn’t seem abstract. And I can’t see the point of it
Problem Detail: The underlying question: What does lambda calculus do for us that we can’t do with the basic function properties and notation generally learned in middle school algebra? First of all, what does abstract mean in the context of lambda Read More …
Maximum length path between any two nodes in a tree with possible negative edge weights
Problem Detail: Is there an efficient way to find the longest path between any two nodes in a tree. Given that edges can have negative weights. I know about the diameter problem which finds the longest path in a graph with Read More …
