Kleene's algorithm: Difference between revisions

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Algorithm description: guessed sect. and page number in Kleene's 1956 paper (not *quite* sure, crosscheck appreciated)
Algorithm description: upper bound for the length of R^k_{ij}
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After that, in each step the expressions ''R''{{su|p=''k''|b=''ij''}} are computed from the previous ones by
:''R''{{su|p=''k''|b=''ij''}} = ''R''{{su|p=''k''-1|b=''ik''}} (''R''{{su|p=''k''-1|b=''kk''}})<sup>*</sup> ''R''{{su|p=''k''-1|b=''kj''}} | ''R''{{su|p=''k''-1|b=''ij''}}
 
By induction on ''k'', it can be shown that the length<ref>More precisely, the number of regular-expression symbols, "''a''<sub>''i''</sub>", "ε", "|", "<sup>*</sup>", "·"; not counting parantheses.</ref> of each expression ''R''{{su|p=''k''|b=''ij''}} is at most {{sfrac|4<sup>''k''+1</sup>(6''s''+7) - 4|3}}, where ''s'' denotes the number of characters in Σ.
 
==Example==