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13/11/2012

Clique in an undirected graph is a subgraph, wherein every 2nodes are connected by an edge.

Clique Problem is to determine whether a graph contains a clique of specified size.

Satisfiability Problem is to test whether a boolean formula is satisfiable. Boolean formula is an expression involving boolean variable & operations. 

Halting Problem is the problem for determining whether a turing m/c halts(by accepting/by rejecting) on a given input.

Decidable  is a problem whose language is recursive. 

A problem is undecidable if there exist no algorithm that takes as input an instance of the problem and determine whether the answer to that instance is "yes" or "no".

Halting Problem is undecidable theorem and proof's scanned copy will upload next day. 

Church's Thesis: - What function cant be computed by turing machines? This is very surprising. It is believed that there are no functions that can be defined by humans,whose calculation can be described by any well defined mathematical algorithm that people can be taught to perform,that cant be computed by TMs. The TM is believed to be the ultimate calculating mechanism. 
Church actually said that any machine that can do certain list of operations will be able to perform all concievable algorithms. he tied together what logicians had called recursive functions and computable functions. TMs can do all that Church's asked, so they are possible model of the universal algorithm machine Church described.

Listen students......
Chomsky Classification/Hierarchy is not equal to Chomsky Normal Form. I will upload some notes about that next day.

Comments

  1. Arun Anoop MNovember 14, 2012 at 4:21 AM

    I had posted the same things in Our students google groups corner...

    MESCE CSE A '10 - '14

    ReplyDelete

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