2015-01-03 06:07:31 +00:00
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inductive day :=
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2015-02-26 01:00:10 +00:00
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monday | tuesday | wednesday | thursday | friday | saturday | sunday
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2015-01-03 06:07:31 +00:00
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open day
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2015-02-26 00:20:44 +00:00
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definition next_weekday : day → day
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| next_weekday monday := tuesday
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| next_weekday tuesday := wednesday
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| next_weekday wednesday := thursday
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| next_weekday thursday := friday
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| next_weekday friday := monday
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| next_weekday saturday := monday
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| next_weekday sunday := monday
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2015-01-03 06:07:31 +00:00
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example : next_weekday (next_weekday monday) = wednesday :=
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rfl
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