Baire category; property of Baire; residual set; upper semicontinuity; Borel set
In this paper we define certain types of projections of planar sets and study some properties of such projections.
 R. Anantharaman and J.P. Lee: Planar sets whose complements do not contain a dense set of lines
. Real Anal. Exch. 11 (1985–86), 168–178. DOI 10.2307/44151737
| MR 0828488
 N.C. Bose Majumder: On some properties of sets with positive measures. Annali Dell’ Univ. di Ferrara (N.S.) Sez VII–Sci. Mat. X (1962), no. 1, 1–12.
 D.K.Ganguly and S. Basu: On some properties of sets with positive measure
. Czechoslovak Math. Jour. 44(119) (1994), 405–411. MR 1288161
 Casper Goffman: Real Functions, Rinehart and Co
. New York, 1953, p. 140. MR 0054006
 T. Katkaniec: On category projections of cartesian product $A \times A$. Real Anal. Exch. 10 (1984–85), 233–234.
 K. Kuratowski: Topology I
. Academic Press, New York, 1966. MR 0217751
 J.C. Oxtoby: Measure and Category, Second Edition
. Springer-Verlag, 1980. MR 0584443
 K.C. Ray: On some properties of ratio sets
. Seminario mathematico dell Universita di Ferrara Ser VII (NS) 11 (1962–65), 45–49. MR 0188366