Different views of objects 对象 by：

1. **Category 范畴** (**morphism*** between Objects, Functors ‘**F**‘ between Cats);

**2. Set 集合** (a “smaller Cat”, only objects);

3. **Type** **类型** (deal only with **same kind **of objects: Int, String, Boulean…).

Note : Category can be a Set (SET) , Group, Ring, Vector Space (Vect) , “Topo” (Topology) … any

algebraic structurewithAssociativeMorphism (Map or ‘Arrow’) between them.

Note (*) : A

morphism态 in layman’s term is best illustrated by geometry:2 triangle objects are similar

= homo相似morphism 同态

2 triangle objects are congruent

全= iso等morphism 同构

Note: Analogy –

Category : School

Type : Boy Class, Girl Class

Set : Students mixed of Boys, Girls