From equality of integrals to equality of functions #
This file provides various statements of the general form "if two functions have the same integral on all sets, then they are equal almost everywhere". The different lemmas use various hypotheses on the class of functions, on the target space or on the possible finiteness of the measure.
Main statements #
All results listed below apply to two functions f, g
, together with two main hypotheses,
f
andg
are integrable on all measurable sets with finite measure,- for all measurable sets
s
with finite measure,∫ x in s, f x ∂μ = ∫ x in s, g x ∂μ
. The conclusion is thenf =ᵐ[μ] g
. The main lemmas are: ae_eq_of_forall_setIntegral_eq_of_sigmaFinite
: case of a sigma-finite measure.AEFinStronglyMeasurable.ae_eq_of_forall_setIntegral_eq
: for functions which areAEFinStronglyMeasurable
.Lp.ae_eq_of_forall_setIntegral_eq
: for elements ofLp
, for0 < p < ∞
.Integrable.ae_eq_of_forall_setIntegral_eq
: for integrable functions.
For each of these results, we also provide a lemma about the equality of one function and 0. For
example, Lp.ae_eq_zero_of_forall_setIntegral_eq_zero
.
We also register the corresponding lemma for integrals of ℝ≥0∞
-valued functions, in
ae_eq_of_forall_setLIntegral_eq_of_sigmaFinite
.
Generally useful lemmas which are not related to integrals:
ae_eq_zero_of_forall_inner
: if for all constantsc
,fun x => inner c (f x) =ᵐ[μ] 0
thenf =ᵐ[μ] 0
.ae_eq_zero_of_forall_dual
: if for all constantsc
in the dual space,fun x => c (f x) =ᵐ[μ] 0
thenf =ᵐ[μ] 0
.
Alias of MeasureTheory.ae_le_of_forall_setLIntegral_le_of_sigmaFinite
.
Alias of MeasureTheory.ae_le_of_forall_setLIntegral_le_of_sigmaFinite₀
.
Alias of MeasureTheory.ae_eq_of_forall_setLIntegral_eq_of_sigmaFinite₀
.
Alias of MeasureTheory.ae_eq_of_forall_setLIntegral_eq_of_sigmaFinite
.
Don't use this lemma. Use ae_nonneg_of_forall_setIntegral_nonneg
.
Alias of MeasureTheory.ae_nonneg_of_forall_setIntegral_nonneg_of_stronglyMeasurable
.
Don't use this lemma. Use ae_nonneg_of_forall_setIntegral_nonneg
.
Alias of MeasureTheory.ae_nonneg_of_forall_setIntegral_nonneg
.
Alias of MeasureTheory.ae_nonneg_restrict_of_forall_setIntegral_nonneg_inter
.
Alias of MeasureTheory.ae_nonneg_of_forall_setIntegral_nonneg_of_sigmaFinite
.
Alias of MeasureTheory.AEFinStronglyMeasurable.ae_nonneg_of_forall_setIntegral_nonneg
.
Alias of MeasureTheory.ae_nonneg_restrict_of_forall_setIntegral_nonneg
.
Alias of MeasureTheory.ae_eq_zero_restrict_of_forall_setIntegral_eq_zero_real
.
Alias of MeasureTheory.ae_eq_zero_restrict_of_forall_setIntegral_eq_zero
.
Alias of MeasureTheory.ae_eq_restrict_of_forall_setIntegral_eq
.
Alias of MeasureTheory.ae_eq_zero_of_forall_setIntegral_eq_of_sigmaFinite
.
Alias of MeasureTheory.ae_eq_of_forall_setIntegral_eq_of_sigmaFinite
.
Alias of MeasureTheory.AEFinStronglyMeasurable.ae_eq_zero_of_forall_setIntegral_eq_zero
.
Alias of MeasureTheory.AEFinStronglyMeasurable.ae_eq_of_forall_setIntegral_eq
.
Alias of MeasureTheory.Lp.ae_eq_zero_of_forall_setIntegral_eq_zero
.
Alias of MeasureTheory.ae_eq_zero_of_forall_setIntegral_eq_of_finStronglyMeasurable_trim
.
Alias of MeasureTheory.Integrable.ae_eq_zero_of_forall_setIntegral_eq_zero
.
Alias of MeasureTheory.Integrable.ae_eq_of_forall_setIntegral_eq
.
If an integrable function has zero integral on all closed sets, then it is zero almost everwhere.
Alias of MeasureTheory.ae_eq_zero_of_forall_setIntegral_isClosed_eq_zero
.
If an integrable function has zero integral on all closed sets, then it is zero almost everwhere.
If an integrable function has zero integral on all compact sets in a sigma-compact space, then it is zero almost everwhere.
If a locally integrable function has zero integral on all compact sets in a sigma-compact space, then it is zero almost everwhere.
Alias of MeasureTheory.AEMeasurable.ae_eq_of_forall_setLIntegral_eq
.