Mathlib Map

Theorems · Theorem · general topology

IsCompact.isClosed

∀ {X : Type u_1} [inst : TopologicalSpace X] [T2Space X] {s : Set X}, IsCompact s → IsClosed s

In a T2Space, every compact set is closed.

Defined in
Mathlib.Topology.Separation.Hausdorff
Cited by
77 results in Mathlib
Foundations
Depth 78 from the axioms · uses propext, Classical.choice, Quot.sound
Assumes
TopologicalSpaceT2Space

Around this declaration

Dashed lines are statement dependencies; solid lines are citations in proofs.

IsCompact.measurableSet · cited by 25IsCompact.measurableSetContinuous.isClosedMap · cited by 9Continuous.isClosedMapFunction.locallyFinsuppWithin.finiteSupport · cited by 9locallyFinsuppWithin.fini…HasCompactSupport.tsupport_extend_zero_subset · cited by 5HasCompactSupport.tsuppor…HasCompactMulSupport.mulTSupport_extend_one_subset · cited by 4HasCompactMulSupport.mulT…Topology.RelCWComplex.isClosed_closedCell · cited by 4RelCWComplex.isClosed_clo…rieszContentAux_image_nonempty · cited by 3rieszContentAux_image_non…LightProfinite.epi_iff_surjective · cited by 3LightProfinite.epi_iff_su…ae_eq_zero_of_integral_contMDiff_smul_eq_zero · cited by 3ae_eq_zero_of_integral_co…isProperMap_iff_isCompact_preimage · cited by 3isProperMap_iff_isCompact…Metric.isCompact_iff_isClosed_bounded · cited by 3Metric.isCompact_iff_isCl…isCompact_setOfPred_finiteMeasure_le_of_isCompact · cited by 2isCompact_setOfPred_finit…loc_compact_Haus_tot_disc_of_zero_dim · cited by 2loc_compact_Haus_tot_disc…ConvexBody.isClosed · cited by 2ConvexBody.isClosedBoxIntegral.integrable_of_bounded_and_ae_continuousWithinAt · cited by 2BoxIntegral.integrable_of…Set · cited by 53352SetTopologicalSpace · cited by 24529TopologicalSpaceFilter · cited by 8121Filternhds · cited by 5554nhdsIsClosed · cited by 1639IsClosedT2Space · cited by 1351T2SpaceIsCompact · cited by 1282IsCompactFilter.NeBot · cited by 853Filter.NeBotFilter.principal · cited by 740Filter.principalClusterPt · cited by 138ClusterPtClusterPt.mono · cited by 30ClusterPt.monoSet.mem_of_eq_of_mem · cited by 8Set.mem_of_eq_of_memClusterPt.neBot · cited by 5ClusterPt.neBotisClosed_iff_forall_filter · cited by 3isClosed_iff_forall_filtereq_of_nhds_neBot · cited by 2eq_of_nhds_neBotIsCompact.isClosedCITED BYCITES

Cites16

Mathlib declarations this one mentions in its statement or cites explicitly in its proof. Plumbing is filtered out.

Cited by77

Results whose statement or proof uses this declaration.