0 a reduction in the amount of money that a company or person spends:
1 a situation in which prices fall suddenly from a high level:
Furthermore, since the bottom, front and top squares are pullbacks, the back square is also a pullback.
This category has weak pullbacks and setindexed products, but, in general, no pullbacks.
The interior operation is not assumed to be natural; that is, it is not assumed to commute with pullbacks.
First it can be easily checked that the following diagram is a pullback.
For example, collections can be zipped if and only if the monad's endofunctor preserves pullbacks.
We will also have use for inverse images, which are pullbacks of two morphisms at least one of which is a monomorphism.
The role of pullbacks in categorical interpretations of logic is to perform substitution of terms into predicates and formulas.
Let be a weak inclusive category that has pullbacks.
