Elements of Non-Euclidean Geometry

Whilst the greatest effort has been made to ensure the quality of this text, due to the historical nature of this content, in some rare cases there may be minor issues with legibility. The heroic age of non-euclidean geometry is passed. It is long since the days when Lobachevsky timidly referred to his system as an ''imaginary geometry'', and the new subject appeared as a dangerous lapse from the ...