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Quod Erat Demonstrandum e.V.
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https://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/quod-erat-demonstrandum
quod erat demonstrandum | Encyclopedia.com
quod erat demonstrandum used to convey that a fact or situation demonstrates the truth of one's theory or claim, especially to mark the conclusion of a formal...
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Creabitur Quod erat demonstrandum - Vicipaedia
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