From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 7 Jun 2017 23:35:24 -0700 (PDT) From: Andrew Swan To: Homotopy Type Theory Cc: wakeli...@gmail.com, awo...@cmu.edu, Thierry...@cse.gu.se Message-Id: <9c8e516a-a09b-4632-8cd1-ccf7a0211cfd@googlegroups.com> In-Reply-To: References: <1128BE39-BBC4-4DC6-8792-20134A6CAECD@chalmers.se> <292DED31-6CB3-49A1-9128-5AFD04B9C2F2@cmu.edu> <9F58F820-A54A-46E7-93DC-F814D4BEE0C6@cmu.edu> Subject: Re: [HoTT] Semantics of higher inductive types MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_215_367460613.1496903724412" ------=_Part_215_367460613.1496903724412 Content-Type: multipart/alternative; boundary="----=_Part_216_1579665615.1496903724412" ------=_Part_216_1579665615.1496903724412 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit > > Why is there no LOG in this? It's a little messy to write out the actual details, but it is possible for each map f : X -> Y to use the subobject classifier and dependent products to construct a "universal lifting problem" for f, where universal means that every other lifting problem against a pushout product of monomorphism and i-endpoint inclusion factors uniquely as a pullback followed by the universal lifting problem. Then, once a filler for the universal lifting problem has been chosen, it can be used to construct a filler for all the other lifting problems. (This can also be seen as an instance of a general result that holds in any locally small fibration with finitely complete base). ------=_Part_216_1579665615.1496903724412 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable
= Why is there no LOG in this?=C2=A0

It's= a little messy to write out the actual details, but it is possible for eac= h map f : X -> Y to use the subobject classifier and dependent products = to construct a "universal lifting problem" for f, where universal= means that every other lifting problem against a pushout product of monomo= rphism and i-endpoint inclusion factors uniquely as a pullback followed by = the universal lifting problem. Then, once a filler for the universal liftin= g problem has been chosen, it can be used to construct a filler for all the= other lifting problems. (This can also be seen as an instance of a general= result that holds in any locally small fibration with finitely complete ba= se).
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