Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Collapse to Black Holes in Brans-Dicke Theory: II. Comparison with
  General Relativity   We discuss a number of long-standing theoretical questions about collapse to
black holes in the Brans-Dicke theory of gravitation. Using a new numerical
code, we show that Oppenheimer-Snyder collapse in this theory produces black
holes that are identical to those of general relativity in final equilibrium,
but are quite different from those of general relativity during dynamical
evolution. We find that there are epochs during which the apparent horizon of
such a black hole passes {\it outside\/} the event horizon, and that the
surface area of the event horizon {\it decreases\/} with time. This behavior is
possible because theorems which prove otherwise assume $R_{ab}l^al^b \ge 0$ for
all null vectors $l^a$. We show that dynamical spacetimes in Brans-Dicke theory
can violate this inequality, even in vacuum, for any value of $\omega$.

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The categories of this paper are: math
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The categories of this paper are: mtrl-th
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The categories of this paper are: cond-mat
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The categories of this paper are: alg-geom
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The categories of this paper are: stat
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The categories of this paper are: q-alg
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The categories of this paper are: physics
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The categories of this paper are: hep-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: nucl-th
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The categories of this paper are: nlin
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The categories of this paper are: plasm-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: eess
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The categories of this paper are: quant-ph
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The categories of this paper are: astro-ph