diff --git a/src/foundation-core/pullbacks.lagda.md b/src/foundation-core/pullbacks.lagda.md index 56f734691a..de2f6bf691 100644 --- a/src/foundation-core/pullbacks.lagda.md +++ b/src/foundation-core/pullbacks.lagda.md @@ -39,18 +39,17 @@ Given a [cospan of types](foundation.cospans.md) we want to pose the question of whether a certain [cone](foundation.cones-over-cospan-diagrams.md) over it is a -{{#concept "pullback cone" Disambiguation="types" Agda=is-pullback}}. This is -concept is captured by +{{#concept "pullback cone" Disambiguation="types" Agda=is-pullback}}. Although +this concept is captured by [the universal property of the pullback](foundation-core.universal-property-pullbacks.md), -however, the universal property is a large proposition so it is not suitable for -all purposes. +this is a large proposition, which is not suitable for all purposes. -As an alternative, given the existence of the +Therefore, as our main definition of a pullback cone we consider +{{#concept "the small predicate of being a pullback" Agda=is-pullback}}: given +the existence of the [standard pullback type](foundation-core.standard-pullbacks.md) `A ×_X B`, we -can characterize pullback cones as those for which the gap map from the standard -pullback is an [equivalence](foundation-core.equivalences.md). This predicate is -a small [proposition](foundation-core.propositions.md) that we dub -{{#concept "the small predicate of being a pullback" Agda=is-pullback}}. +can characterize pullback cones as those for which the gap map into the standard +pullback is an [equivalence](foundation-core.equivalences.md). ## Definitions diff --git a/src/foundation/pullbacks.lagda.md b/src/foundation/pullbacks.lagda.md index 5125d55744..acd402fbea 100644 --- a/src/foundation/pullbacks.lagda.md +++ b/src/foundation/pullbacks.lagda.md @@ -53,18 +53,17 @@ Given a [cospan of types](foundation.cospans.md) we want to pose the question of whether a certain [cone](foundation.cones-over-cospan-diagrams.md) over it is a -{{#concept "pullback cone" Disambiguation="types" Agda=is-pullback}}. This is -concept is captured by +{{#concept "pullback cone" Disambiguation="types" Agda=is-pullback}}. Although +this concept is captured by [the universal property of the pullback](foundation-core.universal-property-pullbacks.md), -however, the universal property is a large proposition so it is not suitable for -all purposes. +this is a large proposition, which is not suitable for all purposes. -As an alternative, given the existence of the +Therefore, as our main definition of a pullback cone we consider +{{#concept "the small predicate of being a pullback" Agda=is-pullback}}: given +the existence of the [standard pullback type](foundation-core.standard-pullbacks.md) `A ×_X B`, we -can characterize pullback cones as those for which the gap map from the standard -pullback is an [equivalence](foundation-core.equivalences.md). This predicate is -a small [proposition](foundation-core.propositions.md) that we dub -{{#concept "the small predicate of being a pullback" Agda=is-pullback}}. +can characterize pullback cones as those for which the gap map into the standard +pullback is an [equivalence](foundation-core.equivalences.md). ## Properties