Implicit-explicit two-step peer methods with RK stability for implicit part

We develop a new family of implicit-explicit (IMEX) schemes appropriate for dealing with the systems of differential equations including two non-stiff and stiff parts on the right-hand side. The proposed IMEX schemes are a combination of s\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\varvec{s}$$\end{document}-stage explicit and implicit diagonally implicit two-step peer methods, in which the implicit part of the methods is A\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\varvec{A}$$\end{document}- or L\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\varvec{L}$$\end{document}-stable and also equipped with Runge-Kutta stability property. The order conditions of this class of IMEX schemes are derived for the methods of orer p=s\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\varvec{p}=\varvec{s}$$\end{document} and their stability behavior is analyzed. Some examples of the methods with p=s\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\varvec{p}=\varvec{s}$$\end{document} up to order five are constructed and the performance of the proposed methods is investigated by giving the results of some numerical experiments.