The common demonstrative pronouns are this and that (singular) and these and those (plural). These words are used to take the place of an entire phrase. Demonstrative pronouns should only be used when the meaning is unambiguous.

Constraint programming is a declarative programming method for modeling combinatorial optimization problems in terms of constraints. This is a fairly dense statement, so let us address the concepts one at a time.

Runic artefacts are both textual sources and archaeological artefacts. Because of this it will be important to classify runic artefacts according to both function and inscription.

[Generally, it is a good idea to avoid using too many demonstrative pronouns. An alternative is to use a demonstrative adjective, as this form is often more clear.]