Projection from cardinal numbers to PartENat
#
In this file we define the projection Cardinal.toPartENat
and prove basic properties of this projection.
This function sends finite cardinals to the corresponding natural, and infinite cardinals
to ⊤
.
Equations
- One or more equations did not get rendered due to their size.
Instances For
@[simp]
theorem
Cardinal.toPartENat_apply_of_lt_aleph0
{c : Cardinal.{u_1}}
(h : c < aleph0)
:
toPartENat c = ↑(toNat c)
theorem
Cardinal.toPartENat_apply_of_aleph0_le
{c : Cardinal.{u_1}}
(h : aleph0 ≤ c)
:
toPartENat c = ⊤
@[simp]
theorem
Cardinal.toPartENat_le_iff_of_le_aleph0
{c c' : Cardinal.{u_1}}
(h : c ≤ aleph0)
:
toPartENat c ≤ toPartENat c' ↔ c ≤ c'
theorem
Cardinal.toPartENat_le_iff_of_lt_aleph0
{c c' : Cardinal.{u_1}}
(hc' : c' < aleph0)
:
toPartENat c ≤ toPartENat c' ↔ c ≤ c'
theorem
Cardinal.toPartENat_inj_of_le_aleph0
{c c' : Cardinal.{u_1}}
(hc : c ≤ aleph0)
(hc' : c' ≤ aleph0)
:
toPartENat c = toPartENat c' ↔ c = c'
@[deprecated Cardinal.toPartENat_inj_of_le_aleph0 (since := "2024-12-29")]
theorem
Cardinal.toPartENat_eq_iff_of_le_aleph0
{c c' : Cardinal.{u_1}}
(hc : c ≤ aleph0)
(hc' : c' ≤ aleph0)
:
toPartENat c = toPartENat c' ↔ c = c'
Alias of Cardinal.toPartENat_inj_of_le_aleph0
.
theorem
Cardinal.toPartENat_congr
{α : Type u}
{β : Type v}
(e : α ≃ β)
:
toPartENat (mk α) = toPartENat (mk β)
theorem
Cardinal.mk_toPartENat_eq_coe_card
{α : Type u}
[Fintype α]
:
toPartENat (mk α) = ↑(Fintype.card α)