Let ac072b078e80039b295b8568b88" title="Click to view the MathML source">m,n≥3, e695f77a7f939780026741465" title="Click to view the MathML source">(m−1)(n−1)+2≤p≤mn, and u=mn−p. The set ba03" title="Click to view the MathML source">Ru×n×m of all real tensors with size u×n×m is one to one corresponding to the set of bilinear maps a135fb0" title="Click to view the MathML source">Rm×Rn→Ru. We show that Rm×n×p has plural typical ranks p and b2405f646dfd08f2612976d6" title="Click to view the MathML source">p+1 if and only if there exists a nonsingular bilinear map a135fb0" title="Click to view the MathML source">Rm×Rn→Ru. We show that there is a dense open subset a13e438fac" title="Click to view the MathML source">O of ba03" title="Click to view the MathML source">Ru×n×m such that for any ba5b11b3f82d6a8d34" title="Click to view the MathML source">Y∈O, the ideal of maximal minors of a matrix defined by Y in a certain way is a prime ideal and the real radical of that is the irrelevant maximal ideal if that is not a real prime ideal. Further, we show that there is a dense open subset e4554e20028030ccd0b9b" title="Click to view the MathML source">T of e48167" title="Click to view the MathML source">Rn×p×m and continuous surjective open maps ν:O→Ru×p and b2fd7c31a116d748ca7bdb" title="Click to view the MathML source">σ:T→Ru×p, where b2ff8d498a44" title="Click to view the MathML source">Ru×p is the set of u×p matrices with entries in a1b766c83" title="Click to view the MathML source">R, such that if b25ca5" title="Click to view the MathML source">ν(Y)=σ(T), then e66c7d9980604628dcb00ee46b2"> if and only if the ideal of maximal minors of the matrix defined by Y is a real prime ideal.