-2
votes
1answer
259 views

Em dash or colon in formal writing

In formal writing, should I use an em dash The Earth consists of three layers — crust, mantle, and core. or a colon The Earth consists of three layers: crust, mantle, and core. ?
3
votes
1answer
180 views

Colon between “that is” and formal definition

Is it appropriate to use "that is" followed by a colon when defining something formally? I have the following example: Let γ be the set of groups that hold variables accessed by C, that is: γ ...