This page will contain links to summary accounts of supporting
foundational or background material used on the rest of the site.
You may like to begin in the
[playroom](Playroom.md "Playroom")
for an entertaining introduction to infinity.
Meanwhile, we expect that this page and these resources will be expanded
as Cantor's attic develops.
## Definition of infinity
- Short informal presentation of the concept of
[infinity](Infinity.md "Infinity").
- The [](First_steps.md)
towards infinity.
## Elementary set-theoretic topics
- [transitive](Transitive.md "Transitive")
- [](Ordering_Relations.md)
- [ordinal](Ordinal.md "Ordinal")
- [](Successor%20ordinal.md)
- [](Limit%20ordinal.md)
- [cardinality](Cardinality.md "Cardinality")
- <a href="Axiom_of_choice" class="mw-redirect" title="Axiom of choice">axiom of choice</a>
- [[Club sets and stationary sets|stationary]],
[club](Club%20sets%20and%20stationary%20sets.md "Club")
- <a href="index.php?title=Hereditary_cardinality&action=edit&redlink=1" class="new" title="Hereditary cardinality (page does not exist)">Hereditary cardinality</a>
- <a href="Ultrafilter" class="mw-redirect" title="Ultrafilter">ultrafilter</a>,
<a href="Measure" class="mw-redirect" title="Measure">measure</a>
- [ultrapower](Ultrapower.md "Ultrapower")
- [](Partition%20property.md)
- [model](Model.md "Model")
## Axiomatic set theories
- <a href="Morse-Kelley_set_theory" class="mw-redirect" title="Morse-Kelley set theory">Morse-Kelley set theory</a>
- [](ZFC.md)
- [](Positive_set_theory.md)
- [](Kripke-Platek.md)
- <a href="index.php?title=New_Foundations&action=edit&redlink=1" class="new" title="New Foundations (page does not exist)">New Foundations</a>
## Forcing
- [forcing](Forcing.md "Forcing")
- <a href="index.php?title=Boolean-valued_models&action=edit&redlink=1" class="new" title="Boolean-valued models (page does not exist)">Boolean-valued models</a>
- <a href="index.php?title=Boolean_ultrapowers&action=edit&redlink=1" class="new" title="Boolean ultrapowers (page does not exist)">Boolean ultrapowers</a>