صفحه 1:
ماشین های تورینگ, تشخیص پذیری و تصمیم
پذیری زبان ها
جلسات حل تمرین نظریه زبان ها و ماشین ها
دانشگاه صنعتی شریف
بهار ۸۷
صفحه 2:
(Causverciors
Gkhow thot o oogquage is decidable PP sowe eoumerdior
Pouuverdes the مها ic lexicographic order.
ioPicite deviduble fooquage uso subset.
صفحه 3:
طراحی تصمیم گیر
x,y,z} 6۰۰۰ رطبع) ی وق بك | وى
and s1 and sg are anagrams of each other }
L={0"1" | mn > 1,n=m?}
L= {xyz | € {0,1}4,9 € {0,1} 4} |
PrefixFreepex = {R|R is a regular expression where L(R) is prefix-free}
L= {<M >| <M > is an enooding of a DFA and L(M) is finite}
INFINITEpra = { (A) : Ais a DFA and L(A) is an infinite language }
صفحه 4:
زبان های مکمل-تشخیص پذیر (عايجوصسوه)
EQorg = { (G1,G2) : Gi, Gz are CFGs and L(G1) = L(G2) }
صفحه 5:
زبان های تصمیم پذیر
A={(M) : M isa DFA which doesn’t accept
any string containing an odd number of Is }
L = {(A,R) — DFA A is cqnivalent to the regular expression R}
L={(G) : Gis a CEG over {0,1} and 1* L(G) #0}
صفحه 6:
زبان های تصمیم يذير
Disa Puig wachiue
Oves O toke wore tho k steps oo toput 2?
Oves O tuke wore tho k steps vo sow tpt?
Oves O take sore thoo A steps مج oll opus?
Oves O ever wove the tape head wore thoa A els
صفحه 7:
زبان های تصمیم پذیر
0: 0 the deserts of 0 Parte نا لهس )0( is a Parte
مومت
L = {(D): DFA D, on some input w, visits each one of its states.}
صفحه 8:
زبان های تصمیم ناپذیر
FQere = { (G,H) | G,H are OFGs and L(G) = L(H) }.
T ={(M) | M isa TM that accepts w® whenever it accepts w}.
= {(M,w)|M on input w ever attempts to move its head left
d is on the leftmost tape cell}
W Bry = {(M) |M is a 2-tape Turing machine and there exists
string w such that M on input w writes L/ on the second tape },
صفحه 9:
زبان هایْ تشخیص ناپذیر
B = {(n,m) | Evory n- state machine M cither
halts in less than m steps on an empty input,
or docsn’t halt on an empty input}.
Let I be a Turing-recognizable language and let: TZ be such that it is 1)
not Turing-recognizable. Consider the language:
L! = {Ow | € L}U {lw | w ZL}.
Is L! Turing-decidable, Turing-recognizable, or not even Turing-recognizable?
صفحه 10:
زبان های تشخیص PLE
ترا وه مسا سا و6
L = {<> | Por every put siren wy, D wal alt wahia (DOO |w|° steps }
وه مت oot recoenizable, (Reduce سوواط نم توا
Let Lz = {(M)|M is a Turing machine and L(M) = ))32((
Prove that Ly is not Turing-recognizable
[Just for fun: Is Zo Turing-recognizable?}
FEN = {(M)| M accepts only a finite number of strings} و یه
صفحه 11:
طراحی تشخیص دهنده
Non — Empty > ]> 2 < | M accepts some string}
Let Ly = ((M)|M isa Turing machine and (M) © L(M)}
Prove that Ly is Turing-recognizable.
A={(Gi,G2) : Gi, G2 are CFGs and L(G1) # L(G2) }
صفحه 12:
t7 the Porc dePicitiza bP DOD مسا عووان)
Cxenise 9.9:
Cena Purtey wacker ever vorite the black syspbol vo its tape?
Cun the tape dphobet be the sore us the واه نوت
رح( موی wackice's read head ever be to te sae becotiog te ior
وه متسه
055 اه ره و اه مه لاس ودف 415 د
صفحه 13:
صفحه 14:
مت مدا
© doubly icPicite tape
+ festa POs (h>d)
* ATuring machine with only RIGHT and RESET
moves
* Cyclical Turing machine
۰ A queue automaton
* 2(k) head Turing machine
* Turing machine with k-dimensional tape
< A single tape TM not allowed to change the input -> regular
language
x Only Right and Stay Put moves -> regular language
صفحه 15:
Chee ty the رایمه مساو TO)
Ot eo0st he best |] squares oF put oa tape cos be detereoicicry.
Opki-Oerode سم
Pakennne DL portions S* too Poite cuber of equvdeure chsses thea نآ
0
hepiller, الحو oryukl Oph Derode worven,