Intervals #
THIS FILE IS SYNCHRONIZED WITH MATHLIB4. Any changes to this file require a corresponding PR to mathlib4.
In any preorder α
, we define intervals (which on each side can be either infinite, open, or
closed) using the following naming conventions:
i
: infiniteo
: openc
: closed
Each interval has the name I
+ letter for left side + letter for right side. For instance,
Ioc a b
denotes the inverval (a, b]
.
This file contains these definitions, and basic facts on inclusion, intersection, difference of
intervals (where the precise statements may depend on the properties of the order, in particular
for some statements it should be linear_order
or densely_ordered
).
TODO: This is just the beginning; a lot of rules are missing
Left-open right-open interval
Instances for set.Ioo
Instances for ↥set.Ioo
Left-closed right-open interval
Instances for set.Ico
Left-infinite right-open interval
Instances for set.Iio
Left-closed right-closed interval
Instances for set.Icc
Instances for ↥set.Icc
- set.Icc.semilattice_inf
- set.Icc.semilattice_sup
- set.Icc.lattice
- set.fintype_Icc
- compact_space_Icc
- set.Icc.has_zero
- set.Icc.has_one
- set.Icc.has_mul
- set.Icc.has_pow
- set.Icc.monoid_with_zero
- set.Icc.comm_monoid_with_zero
- set.Icc.cancel_monoid_with_zero
- set.Icc.cancel_comm_monoid_with_zero
- unit_interval.has_zero
- unit_interval.has_one
- unit_interval.nonempty
- unit_interval.has_mul
- unit_interval.connected_space
Left-infinite right-closed interval
Instances for set.Iic
Instances for ↥set.Iic
- set.nonempty_Iic_subtype
- set.Iic.no_min_order
- set.Iic.semilattice_inf
- set.Iic.semilattice_sup
- set.Iic.lattice
- set.Iic.order_top
- set.Iic.order_bot
- set.Iic.bounded_order
- is_modular_lattice.is_modular_lattice_Iic
- is_modular_lattice.complemented_lattice_Iic
- is_atomic.set.Iic.is_atomic
- set.fintype_Iic
- cardinal.set.Iic.small
- ordinal.small_Iic
- set.Iic.infinite
Left-open right-closed interval
Instances for set.Ioc
- set.ord_connected_Ioc
- filter.tendsto_Ioc_at_top_at_top
- filter.tendsto_Ioc_at_bot_at_bot
- filter.tendsto_Ioc_Ici_Ioi
- filter.tendsto_Ioc_Iic_Iic
- filter.tendsto_Ioc_Iio_Iio
- filter.tendsto_Ioc_Ioi_Ioi
- filter.tendsto_Ioc_Icc_Icc
- filter.tendsto_Ioc_pure_bot
- filter.tendsto_Ioc_uIcc_uIcc
- tendsto_Ioc_class_nhds
Left-closed right-infinite interval
Instances for set.Ici
Instances for ↥set.Ici
- set.nonempty_Ici_subtype
- set.Ici.no_max_order
- set.Ici.semilattice_inf
- set.Ici.semilattice_sup
- set.Ici.lattice
- set.Ici.distrib_lattice
- set.Ici.order_bot
- set.Ici.order_top
- set.Ici.bounded_order
- is_modular_lattice.is_modular_lattice_Ici
- is_modular_lattice.complemented_lattice_Ici
- is_coatomic.set.Ici.is_coatomic
- set.fintype_Ici
- set.Ici.infinite
Left-open right-infinite interval
Instances for set.Ioi
In an order without maximal elements, the intervals Ioi
are nonempty.
In an order without minimal elements, the intervals Iio
are nonempty.
Unions of adjacent intervals #
Two infinite intervals #
A finite and an infinite interval #
An infinite and a finite interval #
Two finite intervals, I?o
and Ic?
#
Two finite intervals, I?c
and Io?
#
Two finite intervals with a common point #
We cannot replace <
by ≤
in the hypotheses.
Otherwise for b < a = d < c
the l.h.s. is ∅
and the r.h.s. is {a}
.