2024/07/18 by Banerjee, Arindam, Basu, Saugata
#55N31 #Algebraic Topology (math.AT) #FOS: Mathematics #Primary 14F25 #Secondary 68W30
paper · doi:10.48550/arxiv.2407.13586
Let R be a real closed field, S ⊂ Rn a closed and bounded semi-algebraic set and f = (f1,…,fp):S → Rp a continuous semi-algebraic map. We study the poset module structure in homology induced by the simultaneous filtrations of S by the sub-level sets of the functions fi from an algorithmic and quantitative point of view. For fixed dimensional homology we prove a singly exponential upper bound on the complexity of these modules which are encoded as certain semi-algebraically constructible functions on Rp × Rp. We also deduce for semi-algebraic filtrations of bounded complexity, upper bounds on the number of equivalence classes of finite poset modules that such a filtration induces -- establishing a tight analogy with a well-known graph theoretical result on the "speed'' of algebraically defined graphs.