Commit 2022-07-20 11:04 327259af

refactor(data/dfinsupp/basic): Improve definitional equalities of coercions (#15521) This means that dfinsupp.coe_add etc are true by definition, rather than requiring the application of quotient.induction first. The key change is that the underlying function is no longer "hidden" under the quotient, as it does not need to be. One motivation for this is to make the API more similar to that of finsupp. This change eliminates dfinsupp.pre, instead using {s : multiset ι // ∀ i, i ∈ s ∨ to_fun i = 0} directly. We no longer even need to create a setoid instance, since we can just use trunc. While adjusting some proofs in data/finsupp/interval to use the new definition, this ended up eliminating some decidable arguments. I don't think that is a consequence of this redefinition, and is incidental cleanup that could have been performed separately.