Write a BNF specification where each string in the language starts with x’s followed by y’s followed by z’s, with the following constraint: number of occurrences of y is greater than the number of occurrences of x and z (|y| > |x|+|z|).
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Start by trying the language where `|y|=|x|+|z|`. Then think about what needs to change to get more `y`s. – rici Feb 12 '21 at 21:15
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I figured it out eventually. BNF specification :
<S"> --> <A'> <C'>
<A'> --> x<A'>yy | xyy
<C'> --> yy<C'>z | yyz
Daniel James
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You can't build some valid strings with that specification like `y` or `xyyyz`. – Progman Feb 12 '21 at 21:31