This is an audio version of the Wikipedia Article: https://en.wikipedia.org/wiki/Production_(computer_science) 00:03:47 Grammar generation 00:08:04 See also Listening is a more natural way of learning, when compared to reading. Written language only began at around 3200 BC, but spoken language has existed long ago. Learning by listening is a great way to: - increases imagination and understanding - improves your listening skills - improves your own spoken accent - learn while on the move - reduce eye strain Now learn the vast amount of general knowledge available on Wikipedia through audio (audio article). You could even learn subconsciously by playing the audio while you are sleeping! If you are planning to listen a lot, you could try using a bone conduction headphone, or a standard speaker instead of an earphone. Listen on Google Assistant through Extra Audio: https://assistant.google.com/services/invoke/uid/0000001a130b3f91 Other Wikipedia audio articles at: https://www.youtube.com/results?search_query=wikipedia+tts Upload your own Wikipedia articles through: https://github.com/nodef/wikipedia-tts Speaking Rate: 0.9876425721474336 Voice name: en-US-Wavenet-B "I cannot teach anybody anything, I can only make them think." - Socrates SUMMARY ======= A production or production rule in computer science is a rewrite rule specifying a symbol substitution that can be recursively performed to generate new symbol sequences. A finite set of productions P {\displaystyle P} is the main component in the specification of a formal grammar (specifically a generative grammar). The other components are a finite set N {\displaystyle N} of nonterminal symbols, a finite set (known as an alphabet) Σ {\displaystyle \Sigma } of terminal symbols that is disjoint from N {\displaystyle N} and a distinguished symbol S ∈ N {\displaystyle S\in N} that is the start symbol. In an unrestricted grammar, a production is of the form u → v {\displaystyle u\to v} where u {\displaystyle u} and v {\displaystyle v} are arbitrary strings of terminals and nonterminals however u {\displaystyle u} may not be the empty string. If v {\displaystyle v} is the empty string, this is denoted by the symbol ϵ {\displaystyle \epsilon } , or λ {\displaystyle \lambda } (rather than leave the right-hand side blank). So productions are members of the cartesian product V ∗ N V ∗ × V ∗ = ( V ∗ ∖ Σ ∗ ) × V ∗ {\displaystyle V^{*}NV^{*}\times V^{*}=(V^{*}\setminus \Sigma ^{*})\times V^{*}} ,where V := N ∪ Σ {\displaystyle V:=N\cup \Sigma } is the vocabulary, ∗ {\displaystyle {}^{*}} is the Kleene star operator, V ∗ N V ∗ {\displaystyle V^{*}NV^{*}} indicates concatenation, and ∪ {\displaystyle \cup } denotes set union. If we do not allow the start symbol to occur in v {\displaystyle v} (the word on the right side), we have to replace V ∗ {\displaystyle V^{*}} by ( V ∖ { S } ) ∗ {\displaystyle (V\setminus \{S\})^{*}} on the right side of the cartesian product symbol.The other types of formal grammar in the Chomsky hierarchy impose additional restrictions on what constitutes a production. Notably in a context-free grammar, the left-hand side of a production must be a single nonterminal symbol. So productions are of the form ...

• published: 07 Jun 2019
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