TITLE: Isn't there an algebraic topology criterion for embeddability of an *abstract* simplicial complex in a Euclidean space of *specified* dimension?
QUESTION [6 upvotes]: Some textbooks on algebraic topology define a simplicial complex as a special kind of subset of a Euclidean space (e.g., A. Wallace, p.3). Others define an abstract simplicial complex as a special kind of combinatorial structure (e.g., E. H. Spanier, p. 108). There exists a functor from the category of abstract simplicial complexes and simplicial maps to the category of topological spaces and continuous functions. My question is, what is an algebraic criterion for deciding whether or not there exists an embedding of  the realization of an abstract simplicial complex into a Euclidean space of specified dimension. For example (J. R. Munkres, p. 18) exhibits an abstract simplicial complex whose realization is a Klein bottle, which cannot be embedded in $R^3$.
If a concrete 2-dimensional finite simplicial complex consists of point, line segment, and triangular subsets of 3-dimensional Euclidean space, then obviously there is more information about these simplices and their relationships than is contained in the corresponding abstract simplicial complex. In particular, there are the lengths of the line segments, the angles between connected line segments (one shared point), and the dihedral angles between connected triangles (one shared edge). This is a finite collection of data. My actual motivation for the titular question is the following question. Given an abstract finite simplicial complex together with "lengths" of 1-dimensional abstract simplices, "angles" between connected 1-dimensional abstract simplices, and "dihedral angles" between connected 2-dimensional abstract simplices, is there an algorithm to decide whether there is an embedding of its simplicial realization in 3-dimensional Euclidean space?

REPLY [9 votes]: It is not exactly clear to me what you mean by an algebraic criterion. But Uli Wagner and Martin Tancer have, with various coauthors and in several papers, tried to give an answer to the question of deciding embeddability, see for instance Filakovský, Wagner, and Zhechev - Embeddability of Simplicial Complexes is Undecidable or de Mesmay, Rieck, Sedgwick, and Tancer - Embeddability in $\mathbb R^3$ is NP-hard.
Of course, they are more interested in the complexity aspect, but an intermediate step is always finding a criterion for embeddability, and then checking it.