Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Putting a spin on metamaterials: Mechanical incompatibility as magnetic
  frustration   Mechanical metamaterials present a promising platform for seemingly
impossible mechanics. They often require incompatibility of their elementary
building blocks, yet a comprehensive understanding of its role remains elusive.
Relying on an analogy to ferromagnetic and antiferromagnetic binary spin
interactions, we present a universal approach to identify and analyze
topological mechanical defects for arbitrary building blocks. We underline
differences between two- and three-dimensional metamaterials, and show how
topological defects can steer stresses and strains in a controlled and
non-trivial manner and can inspire the design of materials with hitherto
unknown complex mechanical response.

5
The categories of this paper are: gr-qc
22
The categories of this paper are: chao-dyn
18
The categories of this paper are: econ
3
The categories of this paper are: physics
11
The categories of this paper are: hep-lat
30
The categories of this paper are: q-alg
15
The categories of this paper are: nucl-ex
12
The categories of this paper are: nucl-th
37
The categories of this paper are: supr-con
1
The categories of this paper are: cs
34
The categories of this paper are: chem-ph
35
The categories of this paper are: mtrl-th
32
The categories of this paper are: atom-ph
27
The categories of this paper are: comp-gas
7
The categories of this paper are: hep-th
29
The categories of this paper are: funct-an