Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Formation of Topological Defects   In these lectures, I review cosmological phase transitions and the
topological aspects of spontaneous symmetry breaking. I then discuss the
formation of walls, strings and monopoles during phase transitions including
lattice based studies of defect formation and recent attempts to go beyond the
lattice. The close connection of defect formation with percolation is
described. Open problems and possible future directions are mentioned.

31
The categories of this paper are: ao-sci
29
The categories of this paper are: funct-an
27
The categories of this paper are: comp-gas
26
The categories of this paper are: bayes-an
23
The categories of this paper are: solv-int
15
The categories of this paper are: nucl-ex
35
The categories of this paper are: mtrl-th
8
The categories of this paper are: hep-ex
34
The categories of this paper are: chem-ph
30
The categories of this paper are: q-alg
2
The categories of this paper are: math
24
The categories of this paper are: dg-ga
33
The categories of this paper are: plasm-ph
3
The categories of this paper are: physics
11
The categories of this paper are: hep-lat
5
The categories of this paper are: gr-qc