Proof for minimum number of states for a epsilon free NFA is $2^n$
I have the following question which I could not proceed:
Let
$$L={w in Sigma^* mid text{all symbols of the alphabet occur even times in } w}.
$$
Prove that any NFA accepting $L$ requires $2^n$ states, where $n$ is the size of the alphabet $Sigma$.
I think I came up with a proof for a DFA using the Myhill-Nerode Theorem but I do not know how to generalize it to NFA's.
Edit:Relevant question is answered in https://stackoverflow.com/questions/9068873/how-do-we-know-that-an-nfa-has-a-minimum-amount-of-states .
proof-explanation automata
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I have the following question which I could not proceed:
Let
$$L={w in Sigma^* mid text{all symbols of the alphabet occur even times in } w}.
$$
Prove that any NFA accepting $L$ requires $2^n$ states, where $n$ is the size of the alphabet $Sigma$.
I think I came up with a proof for a DFA using the Myhill-Nerode Theorem but I do not know how to generalize it to NFA's.
Edit:Relevant question is answered in https://stackoverflow.com/questions/9068873/how-do-we-know-that-an-nfa-has-a-minimum-amount-of-states .
proof-explanation automata
add a comment |
I have the following question which I could not proceed:
Let
$$L={w in Sigma^* mid text{all symbols of the alphabet occur even times in } w}.
$$
Prove that any NFA accepting $L$ requires $2^n$ states, where $n$ is the size of the alphabet $Sigma$.
I think I came up with a proof for a DFA using the Myhill-Nerode Theorem but I do not know how to generalize it to NFA's.
Edit:Relevant question is answered in https://stackoverflow.com/questions/9068873/how-do-we-know-that-an-nfa-has-a-minimum-amount-of-states .
proof-explanation automata
I have the following question which I could not proceed:
Let
$$L={w in Sigma^* mid text{all symbols of the alphabet occur even times in } w}.
$$
Prove that any NFA accepting $L$ requires $2^n$ states, where $n$ is the size of the alphabet $Sigma$.
I think I came up with a proof for a DFA using the Myhill-Nerode Theorem but I do not know how to generalize it to NFA's.
Edit:Relevant question is answered in https://stackoverflow.com/questions/9068873/how-do-we-know-that-an-nfa-has-a-minimum-amount-of-states .
proof-explanation automata
proof-explanation automata
edited Nov 29 '18 at 6:20
asked Nov 28 '18 at 2:15
Arda Akdemir
134
134
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The answer to the relevant question refers to
a theorem of [1] that can be used to determine lower bounds on the number of states of a minimal NFA:
Theorem. Let $L subseteq Sigma^*$ be a regular language and suppose that there exist $n$ pairs of words $P = {(u_i, v_i) mid 1 leqslant i leqslant n }$ such that:
$u_iv_i in L$ for $1 leqslant i leqslant n$
$u_jv_i notin L$ for $1 leqslant i,j leqslant n$ and $i not= j$.
Then any NFA accepting $L$ has at least $n$ states.
Suppose that $Sigma = {a_1, dots, a_n}$. For each $i = (i_1, dots, i_n) in {0, 1}^n$, let $u_i = v_i = a_{i_1}^{i_1} a_{i_2}^{i_2} dotsm a_{i_n}^{i_n}$. By construction, $u_i$ and $v_i$ satisfy the conditions (1) and (2). Since $|{0, 1}^n| = 2^n$, any NFA accepting $L$ has at least $2^n$ states.
[1] I. Glaister and J. Shallit, A lower bound technique for the size of nondeterministic finite automata. Information Processing Letters 59 (2), pp. 75–77, (1996). DOI:10.1016/0020-0190(96)00095-6.
Thank you for the answer!
– Arda Akdemir
Nov 29 '18 at 6:20
add a comment |
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1 Answer
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1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
The answer to the relevant question refers to
a theorem of [1] that can be used to determine lower bounds on the number of states of a minimal NFA:
Theorem. Let $L subseteq Sigma^*$ be a regular language and suppose that there exist $n$ pairs of words $P = {(u_i, v_i) mid 1 leqslant i leqslant n }$ such that:
$u_iv_i in L$ for $1 leqslant i leqslant n$
$u_jv_i notin L$ for $1 leqslant i,j leqslant n$ and $i not= j$.
Then any NFA accepting $L$ has at least $n$ states.
Suppose that $Sigma = {a_1, dots, a_n}$. For each $i = (i_1, dots, i_n) in {0, 1}^n$, let $u_i = v_i = a_{i_1}^{i_1} a_{i_2}^{i_2} dotsm a_{i_n}^{i_n}$. By construction, $u_i$ and $v_i$ satisfy the conditions (1) and (2). Since $|{0, 1}^n| = 2^n$, any NFA accepting $L$ has at least $2^n$ states.
[1] I. Glaister and J. Shallit, A lower bound technique for the size of nondeterministic finite automata. Information Processing Letters 59 (2), pp. 75–77, (1996). DOI:10.1016/0020-0190(96)00095-6.
Thank you for the answer!
– Arda Akdemir
Nov 29 '18 at 6:20
add a comment |
The answer to the relevant question refers to
a theorem of [1] that can be used to determine lower bounds on the number of states of a minimal NFA:
Theorem. Let $L subseteq Sigma^*$ be a regular language and suppose that there exist $n$ pairs of words $P = {(u_i, v_i) mid 1 leqslant i leqslant n }$ such that:
$u_iv_i in L$ for $1 leqslant i leqslant n$
$u_jv_i notin L$ for $1 leqslant i,j leqslant n$ and $i not= j$.
Then any NFA accepting $L$ has at least $n$ states.
Suppose that $Sigma = {a_1, dots, a_n}$. For each $i = (i_1, dots, i_n) in {0, 1}^n$, let $u_i = v_i = a_{i_1}^{i_1} a_{i_2}^{i_2} dotsm a_{i_n}^{i_n}$. By construction, $u_i$ and $v_i$ satisfy the conditions (1) and (2). Since $|{0, 1}^n| = 2^n$, any NFA accepting $L$ has at least $2^n$ states.
[1] I. Glaister and J. Shallit, A lower bound technique for the size of nondeterministic finite automata. Information Processing Letters 59 (2), pp. 75–77, (1996). DOI:10.1016/0020-0190(96)00095-6.
Thank you for the answer!
– Arda Akdemir
Nov 29 '18 at 6:20
add a comment |
The answer to the relevant question refers to
a theorem of [1] that can be used to determine lower bounds on the number of states of a minimal NFA:
Theorem. Let $L subseteq Sigma^*$ be a regular language and suppose that there exist $n$ pairs of words $P = {(u_i, v_i) mid 1 leqslant i leqslant n }$ such that:
$u_iv_i in L$ for $1 leqslant i leqslant n$
$u_jv_i notin L$ for $1 leqslant i,j leqslant n$ and $i not= j$.
Then any NFA accepting $L$ has at least $n$ states.
Suppose that $Sigma = {a_1, dots, a_n}$. For each $i = (i_1, dots, i_n) in {0, 1}^n$, let $u_i = v_i = a_{i_1}^{i_1} a_{i_2}^{i_2} dotsm a_{i_n}^{i_n}$. By construction, $u_i$ and $v_i$ satisfy the conditions (1) and (2). Since $|{0, 1}^n| = 2^n$, any NFA accepting $L$ has at least $2^n$ states.
[1] I. Glaister and J. Shallit, A lower bound technique for the size of nondeterministic finite automata. Information Processing Letters 59 (2), pp. 75–77, (1996). DOI:10.1016/0020-0190(96)00095-6.
The answer to the relevant question refers to
a theorem of [1] that can be used to determine lower bounds on the number of states of a minimal NFA:
Theorem. Let $L subseteq Sigma^*$ be a regular language and suppose that there exist $n$ pairs of words $P = {(u_i, v_i) mid 1 leqslant i leqslant n }$ such that:
$u_iv_i in L$ for $1 leqslant i leqslant n$
$u_jv_i notin L$ for $1 leqslant i,j leqslant n$ and $i not= j$.
Then any NFA accepting $L$ has at least $n$ states.
Suppose that $Sigma = {a_1, dots, a_n}$. For each $i = (i_1, dots, i_n) in {0, 1}^n$, let $u_i = v_i = a_{i_1}^{i_1} a_{i_2}^{i_2} dotsm a_{i_n}^{i_n}$. By construction, $u_i$ and $v_i$ satisfy the conditions (1) and (2). Since $|{0, 1}^n| = 2^n$, any NFA accepting $L$ has at least $2^n$ states.
[1] I. Glaister and J. Shallit, A lower bound technique for the size of nondeterministic finite automata. Information Processing Letters 59 (2), pp. 75–77, (1996). DOI:10.1016/0020-0190(96)00095-6.
answered Nov 28 '18 at 17:36
J.-E. Pin
18.3k21754
18.3k21754
Thank you for the answer!
– Arda Akdemir
Nov 29 '18 at 6:20
add a comment |
Thank you for the answer!
– Arda Akdemir
Nov 29 '18 at 6:20
Thank you for the answer!
– Arda Akdemir
Nov 29 '18 at 6:20
Thank you for the answer!
– Arda Akdemir
Nov 29 '18 at 6:20
add a comment |
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