Correct superset to subset on ISet<T>.IsProperSupersetOf

[nlov]

Type of issue

Typo

Description

Current text in the Remarks section of method IsProperSupersetOf states
"An empty set is a proper superset of any other collection."
It should state
"An empty set is a proper subset of any other collection."
as found on the page for IsProperSubsetOf:
2025 07 02 ISet.IsProperSubsetOf(IEnumerable) Method (System.Collections.Generic) | Microsoft Learn

Page URL

https://learn.microsoft.com/en-us/dotnet/api/system.collections.generic.iset-1.ispropersupersetof?view=net-9.0#system-collections-generic-iset-1-ispropersupersetof(system-collections-generic-ienumerable((-0)))

Content source URL

https://github.com/dotnet/dotnet-api-docs/blob/main/xml/System.Collections.Generic/ISet`1.xml

Document Version Independent Id

817d0132-55c5-f846-8392-949dd24c7863

Platform Id

62938d6f-b4f5-d893-12f2-4a50b1d4e6e0

Article author

@dotnet-bot

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Tagging subscribers to this area: @dotnet/area-system-collections

[kanilsz]

@nlov why in IsProperSupersetOf should it be stated that this is a proper subset?
Current description looks proper as for IsProperSupersetOf.

[nlov]

Hello @kanilsz, thanks for reviewing this! I was correct in that the wording did need to be changed.

Mathematically, an empty set should always be considered to be a subset of any other set, even if not necessarily a proper subset (since we could be comparing an empty set to another empty set).

So, I was partially correct, but plain "subset" instead of "proper subset" is correct.

In #11855 merged a few weeks ago, it looks like we have fixed this. Closing this issue.