[Merged by Bors] - feat(data/set/basic): symm_diff lemmas
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src/data/set/basic.lean
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| h.le_symm_diff_sup_symm_diff_right | ||
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| @[simp] lemma symm_diff_nonempty : (s ∆ t).nonempty ↔ s ≠ t := | ||
| ne_empty_iff_nonempty.symm.trans symm_diff_eq_bot.not |
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Should symm_diff_eq_bot be duplicated as symm_diff_eq_empty?
eric-wieser
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| @@ -1584,12 +1596,19 @@ begin | |||
| exact image_subset f (subset_union_right t s) | |||
| end | |||
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| lemma subset_image_symm_diff : (f '' s) ∆ (f '' t) ⊆ f '' s ∆ t := | |||
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Suggested change
| lemma subset_image_symm_diff : (f '' s) ∆ (f '' t) ⊆ f '' s ∆ t := | |
| lemma subset_image_symm_diff {f : α → β} : (f '' s) ∆ (f '' t) ⊆ f '' s ∆ t := |
to match all the other nearby lemmas.
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symm_diff lemmassymm_diff lemmas
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A few lemma about
symm_diff, and their translation toset.From Con(NF)