At least one of Ann and Bill was present Ann and Bill weren’t both absent ¬ (¬ A ∧ ¬ B) (> 0 of them were there)	▿	Ann and Bill weren’t both present At least one of Ann and Bill was absent ¬ (A ∧ B) (< 2 of them were there)
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Ann and Bill were both present Neither Ann nor Bill was absent A ∧ B (2 of them were there)	▵	Neither Ann nor Bill was present Ann and Bill were both absent ¬ A ∧ ¬ B (0 of them were there)