subtyping
サブタイピング
Covariance and contravariance
The circle-ellipse problem (for the perils of subtyping variable-types on the same basis as value-types)
class-based programming
Top type
Refinement type
Behavioral subtyping
/suto3/google.iconsubtyping
/suto3/Google画像検索.iconsubtyping
/suto3/Google定義検索.icon subtyping
/suto3/wikipedia.iconsubtyping
/suto3/weblio.icon subtyping
/suto3/kotobank.icon subtyping
/suto3/jisho.icon subtyping