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feat(analysis/normed_space/lattice_ordered_group): Lattice ordered group lemmas #9548
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Co-authored-by: Eric Wieser <wieser.eric@gmail.com>
Co-authored-by: Eric Wieser <wieser.eric@gmail.com>
Co-authored-by: Eric Wieser <wieser.eric@gmail.com>
Co-authored-by: Eric Wieser <wieser.eric@gmail.com>
Thank you for this PR @mans0954 and thank you for your patience with this PR. I'm sorry that this proposal has been open for so long without resolution so I've just taken a careful look to see what we can do. It looks to me like there are four things happening here:
Do you think you would be able to split it up, into several PRs, perhaps (but not necessarily) along the lines above so that it is easier to focus on each of the various changes? Though the various pieces are related, each of them is likely to need discussion in its own right. |
I could do that it it would help? 1) and 2) were the outcome of previous review of this PR #9548 (review) #9548 (review) and 4) is motivated by feedback on a previous PR #8663 (review) and #8673 (comment) . The impact of changes 1) and 2) is limited to code I wrote in my recent PRs #8673, #9172, #9274, which, together with this PR are building towards #10322. |
… lattice-ordered-group-lemmas
…multaplicative form (#10419) Currently mathlib has a rich set of lemmas connecting the addition, subtraction and negation additive group operations, but a far thinner collection of results for multiplication, division and inverse multiplicative group operations, despite the fact that the former can be generated easily from the latter via `to_additive`. In #9548 I require multiplicative forms of the existing `sub_add_cancel` and `neg_sub` lemmas. This PR refactors them as the equivalent multiplicative results and then recovers `sub_add_cancel` and `neg_sub` via `to_additive`. There is a complication in that unfortunately `group_with_zero` already has lemmas named `inv_div` and `div_mul_cancel`. I have worked around this by naming the lemmas in this PR `inv_div'` and `div_mul_cancel'` and then manually overriding the names generated by `to_additive`. Other suggestions as to how to approach this welcome.
🎉 Great news! Looks like all the dependencies have been resolved:
💡 To add or remove a dependency please update this issue/PR description. Brought to you by Dependent Issues (:robot: ). Happy coding! |
…multaplicative form (#10419) Currently mathlib has a rich set of lemmas connecting the addition, subtraction and negation additive group operations, but a far thinner collection of results for multiplication, division and inverse multiplicative group operations, despite the fact that the former can be generated easily from the latter via `to_additive`. In #9548 I require multiplicative forms of the existing `sub_add_cancel` and `neg_sub` lemmas. This PR refactors them as the equivalent multiplicative results and then recovers `sub_add_cancel` and `neg_sub` via `to_additive`. There is a complication in that unfortunately `group_with_zero` already has lemmas named `inv_div` and `div_mul_cancel`. I have worked around this by naming the lemmas in this PR `inv_div'` and `div_mul_cancel'` and then manually overriding the names generated by `to_additive`. Other suggestions as to how to approach this welcome.
This reverts commit 9a3e6de.
I think everything of use in this PR has now been merged via other smaller PRs, so closing. |
Adds some useful lattice ordered group lemmas, needed by #10322.
has_pos_part
andhas_neg_part
classes #10420