Description: The set of closed subspaces of a Hilbert space exists (is a set). (Contributed by NM, 23-Oct-1999) (New usage is discouraged.)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | chex | ⊢ Cℋ ∈ V | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | shex | ⊢ Sℋ ∈ V | |
| 2 | chsssh | ⊢ Cℋ ⊆ Sℋ | |
| 3 | 1 2 | ssexi | ⊢ Cℋ ∈ V |