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Dec 7, 2011 at 0:25 comment added Mike Shulman Beautiful! That's all I could have hoped for. Someone should really work all of this out and write it up.
Dec 6, 2011 at 16:39 history edited Charles Rezk CC BY-SA 3.0
clarification
Dec 6, 2011 at 16:22 comment added Charles Rezk (1) I mean Reedy fibration. It turns out that if W is a CSS, and f is a Reedy fibration with the above property, then X is also a CSS, and thus f (being a Reedy fibration between CSS's) is also a fibration in the CSS model category. (2) I believe it is a fibration if $\delta$ is injective, but not generally. (In the condition describing fibrant objects, it actually suffices to require a weak equivalence only in the case $\delta:[0]\to [p]$.) (3) Yup. (4) Yup.
Dec 6, 2011 at 0:47 vote accept Mike Shulman
Dec 6, 2011 at 0:47 comment added Mike Shulman Also, (3) I presume that this model structure is constructed as a localization of some over-model-structure for simplicial spaces over W? And (4, I guess) does that imply that the weak equivalences between fibrant objects in this model structure are still just the levelwise equivalences?
Dec 6, 2011 at 0:45 comment added Mike Shulman Thanks! Two questions. (1) By "fibrations $f\colon X\to W$", do you mean Reedy fibrations? Or fibrations in the CSS model structure? (2) Is the "evident map" necessarily itself a fibration (say, if $f$ is a fibration according to your answer to (1))?
Dec 5, 2011 at 15:57 history answered Charles Rezk CC BY-SA 3.0