Semi Post-Widder Operators and Difference Estimates

We consider the Post-Widder operators of semi-exponential type, which are a generalization of the exponential operators connected with x(2). This modification has the beauty to find difference with other operators, while the original Post-Widder operators do not have such property. We estimate quantitative difference of these operators with Baskakov type operators and Szasz-Kantorovich operators, along with some composition of operators. Finally, we further consider a form preserving linear functions and estimate some direct results.