9,756 research outputs found
Heterogeneous Homebuyers, Mortgage Choice and the use of Mortgage Brokers
Choosing a mortgage product in the face of labor income risk, interest rate risk and borrowing constraints is one of the most important decisions facing a household. This paper investigates the choice between a variety of fixed rate mortgages and adjustable rate mortgages. We find that households with a high loan-to-value ratio, risky income and high risk aversion are more likely to choose a fixed rate mortgage. Choosing a mortgage product relies market search and information. The paper finds that in general first-time homebuyers and those with a high loan-to-value ratio are more likely to use a mortgage broker.Mortgage choice,First-time homebuyer,Mortgage broker
Integrating factors for second order ODEs
A systematic algorithm for building integrating factors of the form mu(x,y),
mu(x,y') or mu(y,y') for second order ODEs is presented. The algorithm can
determine the existence and explicit form of the integrating factors themselves
without solving any differential equations, except for a linear ODE in one
subcase of the mu(x,y) problem. Examples of ODEs not having point symmetries
are shown to be solvable using this algorithm. The scheme was implemented in
Maple, in the framework of the "ODEtools" package and its ODE-solver. A
comparison between this implementation and other computer algebra ODE-solvers
in tackling non-linear examples from Kamke's book is shown.Comment: 21 pages - original version submitted Nov/1997. Related Maple
programs for finding integrating factors together with the ODEtools package
(versions for MapleV R4 and MapleV R5) are available at
http://lie.uwaterloo.ca/odetools.ht
Solving the kilo-second QPO problem of the intermediate polar GK Persei
We detect the likely optical counterpart to previously reported X-ray QPOs in
spectrophotometry of the intermediate polar GK Persei during the 1996 dwarf
nova outburst. The characteristic timescales range between 4000--6000 s.
Although the QPOs are an order of magnitude longer than those detected in the
other dwarf novae we show that a new QPO model is not required to explain the
long timescale observed. We demonstrate that the observations are consistent
with oscillations being the result of normal-timescale QPOs beating with the
spin period of the white dwarf. We determine the spectral class of the
companion to be consistent with its quiescent classification and find no
significant evidence for irradiation over its inner face. We detect the white
dwarf spin period in line fluxes, V/R ratios and Doppler-broadened emission
profiles.Comment: 14 pages, 11 figures. Accepted for publication in MNRA
Variations on the Sum-Product Problem
This paper considers various formulations of the sum-product problem. It is
shown that, for a finite set ,
giving a partial answer to a
conjecture of Balog. In a similar spirit, it is established that
a bound which is optimal up to
constant and logarithmic factors. We also prove several new results concerning
sum-product estimates and expanders, for example, showing that
holds for a typical element of .Comment: 30 pages, new version contains improved exponent in main theorem due
to suggestion of M. Z. Garae
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