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lat:homework [2009/11/27 22:44]
barbara.jobstmann
lat:homework [2009/12/06 12:30]
radu.iosif
Line 1: Line 1:
-[[LAT|Back to course homepage.]] +[[:lat|Back to course homepage.]]
 ====== LAT Homework ====== ====== LAT Homework ======
 +
 +===== 02.10.2009 =====
 +
 +Consider the automata construction from proof of the Myhill-Nerode theorem for a language L. Prove 
 +  * (a) the constructed automaton A is the minimal automaton (in the number of states) that recognizes L;
 +  * (b) any minimal automaton recognizing L is isomorphic to A.
 +
 +
 +===== 06.11.2009 =====
 +
 +     - Given a reachability game (G,F), give an algorithm that computes the 0-Attractor(F) set in time O(|E|).
 +     - Consider the game graph shown in below and the following winning conditions: a) Occ(ρ) ∩ {1} ≠ ∅ and b) Occ(ρ) ⊆ {1,​2,​3,​4,​5,​6} and c) Inf(ρ) ∩ {4,5} ≠ ∅. Compute the winning regions and corresponding winning strategies showing the intermediate steps (i.e., the Attractor and Recurrence sets) of the computation.\\ {{hw1.gif|Figure 1}}
 +     - Given a game graph G=(S,​S<​sub>​0</​sub>,​T) and a set F ⊆ S. Let W<​sub>​0</​sub>​ and W_1 be the winning regions of Player 0 and Player 1, respectively,​ in the Buchi game (G,​F). ​ Prove or disprove: ​
 +       - The winning set of Player 0 in the safety game for (G,​W<​sub>​0</​sub>​) is W<​sub>​0</​sub>, ​
 +       - If f<​sub>​0</​sub>​ is a winning strategy for Player 0 in the safety game for (G,​W<​sub>​0</​sub>​),​ then f<​sub>​0</​sub>​ is also a winning strategy for Player 0 in the Buchi game for (G,​F),  ​
 +       - the winning set of Player 1 in the guaranty game for (G,W_1) is W_1, and 
 +       - if f_1 is a winning strategy for Player 1 in the guaranty game for (G,​W<​sub>​0</​sub>​),​ then f_1 is a winning strategy in the Buchi game (G,​F). ​
 +
 +===== 13.11.2009 =====
 +
 +     - Consider the game graph shown below. ​ Let the winning condition for Player 0 be Occ(ρ)={1,​2,​3,​4,​5,​6,​7}
 +        - Find the winning region for Player 0 and describe a winning strategy
 +        - Show that there is no positional winning strategy for Player 0 in this game.\\ {{hw3.gif|Figure 2}}
 +     - Compute the winning regions and the corresponding positional winning strategies for Player 0 and 1 in the weak-parity game shown below. {{hw2.gif|Figure 3}}
 +     - A winning strategy is called "​uniform"​ if it is a winning strategy from every winning state in the game.  Let (G,p) be a weak parity game and let W<​sub>​0</​sub>​ be the winning region of Player 0. For all s ∈ W<​sub>​0</​sub>​ let f_s be a positional winning strategy from s for Player 0. Construct a uniform winning strategy f from the strategies f_s meaning that for every s ∈ W<​sub>​0</​sub>​ there is a t ∈ W<​sub>​0</​sub>,​ s.t. f(s) = f_t(s).
 +
 +===== 27.11.2009 =====
 +
 +     - Consider the game graph below and the Muller condition F={{2,​4,​5,​7},​{1,​2,​3,​4,​5,​6,​7}}. Find an automaton winning strategy for Player 0 in the Muller game with as few states as possible and show that any other automaton strategy with less states is not winning for Player 0.\\ {{hw4.gif}}
 +     - Consider the game shown on page 6 of {{:​slide10.pdf}}. We propose the following "​latest appearance queue" (LAQ) strategy for Player 0, initializing the queue with s<​sub>​1</​sub>​s<​sub>​2</​sub>​s<​sub>​3</​sub>​s<​sub>​4</​sub>,​
 +        - add the current state at the front of the LAQ and delete the last state
 +        - move to the state t<​sub>​i</​sub>​ whose number i is the number of different states in the current LAQ,\\ e.g., for the sequence of states s<​sub>​1</​sub>,​ s<​sub>​3</​sub>,​ s<​sub>​3</​sub>,​ s<​sub>​4</​sub>,​ s<​sub>​1</​sub>,​... we obtain the following sequence of LAQs: s<​sub>​1</​sub>​s<​sub>​2</​sub>​s<​sub>​3</​sub>​s<​sub>​4</​sub>,​ s<​sub>​1</​sub>​s<​sub>​1</​sub>​s<​sub>​2</​sub>​s<​sub>​3</​sub>,​ s<​sub>​3</​sub>​s<​sub>​1</​sub>​s<​sub>​1</​sub>​s<​sub>​2</​sub>,​ s<​sub>​3</​sub>​s<​sub>​3</​sub>​s<​sub>​1</​sub>​s<​sub>​1</​sub>,​ s<​sub>​4</​sub>​s<​sub>​3</​sub>​s<​sub>​3</​sub>​s<​sub>​1</​sub>,​s<​sub>​1</​sub>​s<​sub>​4</​sub>​s<​sub>​3</​sub>​s<​sub>​3</​sub>,​...\\ Decide wheater the new LAQ strategy is a winning strategy for Player 0. Prove this or give a counter-example.
 +     - Let A=(S,​s<​sub>​0</​sub>,​T,​p) be a parity automaton with p:S -> {1,..,k}. Construct a Streett automaton B=(S,​s<​sub>​0</​sub>,​T,​F) equivalent to A that has the same transition structure as A. (i.e., find a suitable set of Streett pairs (F_i,E_i))
 +
 +===== 6.12.2009 =====
 +
 + - Exam-like problems on automata and Presburger Arithmetic {{homework.ps}}