blackboard bold

blackboard bold is a typeface.

Also recorded as double-struck; double struck.

Overview

It is associated with France. Catalogue entries for printed books state edition, collation, binding and condition. VALÉORINE records this subject so that lots referring to it can be described consistently.

In detail

typeface, used in mathematics, that doubles certain lines of the symbol

Sources

Each source is named with the standing the house places on it, so the evidence can be weighed rather than taken on trust.

reference work · Reputable secondary · Wikipedia
“Blackboard bold”, English Wikipedia, consulted as further reading
Consult the source
reference work · Reputable secondary · Wikidata
Wikidata, structured authority record Q1142171: blackboard bold
Consult the source