Example CAEHW, "the" to "this" (Jenna Fontaine)
Example CAEHW, added an "and" (Anna Dovzhik)
Sage CEVAL, "be" to "by" (Anna Dovzhik)
Example BDE, removed stale link (Anna Dovzhik)
Theorem HMOE, second step of proof justified by Property DCN (Anna Dovzhik)