PPT-Undecidable Languages

Chapter 42 H éctor MuñozAvila Undecidable Languages We are going to make 2 proofs An existence proof We show that a language L must exist that cannot be decidedrecognized with . Class 18: . Proving Undecidability. Spring 2010. University of Virginia. David Evans. Menu. Revisiting the Halting Problem . Proof by Paradox. Universal Programming Languages. Reduction Proofs. Barbara . Theory of Computation. Alexander . Tsiatas. Spring 2012. Theory of Computation Lecture Slides by Alexander . Tsiatas. is licensed under a Creative Commons Attribution-. NonCommercial. -. ShareAlike. This story starts with Jack..  . Here he is. . He is miserable..  . And here is his mother.. She is angry..  . And this is their house.. It is falling down..  . And this is their cow.. She seems OK.. Unit 9: . Undecidability. [Slides . adapted from . Amos Israeli’s]. Limits to computation. There are problems for which there cannot be an algorithm, provably.. Undecidable problems. There are problems for which polynomial-time algorithms are unlikely to exist. Homework. HW8 due Tues 5/29 11am. HW5 grades are out. Monday is Memorial Day; no office hours, etc.. Go see a parade, or some fireworks, or something. TA Evaluations at the end of class. !. There’s a lot of stuff in today’s lecture. 1. 2. Text book Pages 187– 199. Reducibility. A . reduction. . is a way of converting one problem to another problem in such . a way . that a solution to the second problem can be used to solve the first problem. Lecture14: Recap. Prof. Amos Israeli. Regular languages – Finite automata.. Context free languages – Stack automata.. Decidable languages – Turing machines.. Undecidability.. Reductions.. Subjects. Class 17: . Undecidable Languages. Spring 2010. University of Virginia. David Evans. Menu. Another . Self-Rejecting . argument: . diagonalization. A language that is . Turing-recognizable. but not . This story starts with Jack..  . Here he is. . He is miserable..  . And here is his mother.. She is angry..  . And this is their house.. It is falling down..  . And this is their cow.. She seems OK.. Sipser. 5.1 (pages 187-198). Reducibility. Driving directions. Western Mass. Cambridge. Boston. If you can’t drive to London…. If something’s impossible…. Theorem 4.11: . A. TM. = {. <. Fall 2017. http://cseweb.ucsd.edu/. classes/fa17/cse105-a/. Today's learning goals . Sipser Ch 5.1. Define and explain core examples of decision problems: A. DFA. , E. DFA. , EQ. DFA. , A. TM. , . HALT. Learning . Objectives. At the conclusion of the chapter, the student will be able to:. Explain and differentiate the concepts of computability and decidability. Define the Turing machine halting problem. The halting problem is . undecidable. Decidability. Undecidability. decidable  RE  all languages. our goal: prove these containments proper. regular languages. context free languages. all languages. A mother language is spoken by groups of people who become separated by time and distance. Those groups then form new languages based on a common origin.. LANGUAGE FAMILY. : a collection of languages related through a common ancestral language that existed before recorded history. (Indo-European is the world’s most extensive language family.).