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16 lines
734 B
Plaintext
16 lines
734 B
Plaintext
Rules for implicit quantification in Mercury
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If a variable occurs in a negated context (inside a negation, inside a
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universal quantification, in the condition of an if-then-else, or in a
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disequality), and which does not occur outside of that negated context
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other than in "parallel" goals (and in the case of a variable in the
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condition of an if-then-else, other than in the "then" part of the
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if-then-else), then that variable is implicitly existentially
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quantified inside the negation.
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"Parallel" goals are defined as follows: different branches of a
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disjunction are parallel; and the "else" part of an if-then-else is
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parallel to the condition and the "then" part (and vice versa).
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