diff --git a/src/simplicial-hott/13-limits.rzk.md b/src/simplicial-hott/13-limits.rzk.md index 2442b580..0af7298a 100644 --- a/src/simplicial-hott/13-limits.rzk.md +++ b/src/simplicial-hott/13-limits.rzk.md @@ -82,15 +82,17 @@ definitions coincide. Define cone as a family. ( b x : B ) ( k : hom B b x) : ( family-cone A B f x) → ( family-cone A B f b) - := \ α → vertical-comp-nat-trans - ( A) - ( \ a → B) - ( \ a → is-segal-B) - ( constant A B b) - ( constant A B x) - ( f) - ( constant-nat-trans A B b x k) - ( α) + := + \ α + → vertical-comp-nat-trans + ( A) + ( \ _ → B) + ( \ _ → is-segal-B) + ( constant A B b) + ( constant A B x) + ( f) + ( constant-nat-trans A B b x k) + ( α) ``` Another definition of limit. @@ -102,9 +104,9 @@ Another definition of limit. ( f : A → B) : U := Σ (b : B), - Σ ( c : family-cone A B f b) - , ( x : B) → ( k : hom B b x) - → is-equiv + Σ ( c : family-cone A B f b) + , ( x : B) → ( k : hom B b x) + → is-equiv ( family-cone A B f x) ( family-cone A B f b) ( cone-precomposition A B is-segal-B f b x k) @@ -126,15 +128,17 @@ definitions coincide. Define cocone as a family. ( x b : B) ( k : hom B x b) : ( family-cocone A B f x) → ( family-cocone A B f b) - := \ α → vertical-comp-nat-trans - ( A) - ( \ a → B) - ( \ a → is-segal-B) - ( f) - ( constant A B x) - ( constant A B b) - ( α) - ( constant-nat-trans A B x b k ) + := + \ α + → vertical-comp-nat-trans + ( A) + ( \ _ → B) + ( \ _ → is-segal-B) + ( f) + ( constant A B x) + ( constant A B b) + ( α) + ( constant-nat-trans A B x b k ) ``` Another definition of colimit. @@ -146,12 +150,12 @@ Another definition of colimit. ( f : A → B) : U := Σ (b : B), - Σ ( c : family-cocone A B f b) - , ( x : B) → ( k : hom B x b) - → is-equiv - ( family-cocone A B f x) - ( family-cocone A B f b) - ( cocone-postcomposition A B is-segal-B f x b k) + Σ ( c : family-cocone A B f b) + , ( x : B) → ( k : hom B x b) + → is-equiv + ( family-cocone A B f x) + ( family-cocone A B f b) + ( cocone-postcomposition A B is-segal-B f x b k) ``` The following alternative definition does not require a Segalness condition. @@ -245,18 +249,18 @@ The type of cocones of a function with codomain a Segal type is a Segal type. : is-covariant B ( \ b → family-cocone A B f b) := is-covariant-substitution-is-covariant - ( A → B) - ( B) - ( hom ( A → B) f) - ( is-covariant-representable-is-segal - ( A → B) - ( is-segal-function-type - ( funext) - ( A) - ( \ _ → B) - ( \ _ → is-segal-B)) - ( f)) - ( \ b → constant A B b) + ( A → B) + ( B) + ( hom ( A → B) f) + ( is-covariant-representable-is-segal + ( A → B) + ( is-segal-function-type + ( funext) + ( A) + ( \ _ → B) + ( \ _ → is-segal-B)) + ( f)) + ( \ b → constant A B b) #def is-segal-cocone-is-segal uses (funext) ( A B : U) @@ -265,15 +269,15 @@ The type of cocones of a function with codomain a Segal type is a Segal type. : is-segal ( cocone A B f) := is-segal-total-type-covariant-family-is-segal-base - ( naiveextext) + ( naiveextext) + ( B) + ( family-cocone A B f) + ( is-covariant-family-cone-is-segal + ( A) ( B) - ( family-cocone A B f) - ( is-covariant-family-cone-is-segal - ( A) - ( B) - ( is-segal-B) - ( f)) ( is-segal-B) + ( f)) + ( is-segal-B) ``` Colimits are unique up to isomorphism. @@ -285,16 +289,16 @@ Colimits are unique up to isomorphism. ( f : A → B) ( x y : colimit A B f) : Iso - ( cocone A B f) - ( is-segal-cocone-is-segal A B is-segal-B f) - ( first x) - ( first y) + ( cocone A B f) + ( is-segal-cocone-is-segal A B is-segal-B f) + ( first x) + ( first y) := iso-initial - ( cocone A B f) - ( is-segal-cocone-is-segal A B is-segal-B f) - ( first x) - ( first y) - ( second x) - ( second y) + ( cocone A B f) + ( is-segal-cocone-is-segal A B is-segal-B f) + ( first x) + ( first y) + ( second x) + ( second y) ```