Carl, S.; Heikkilä, S. Fixed point theorems for multivalued operators and application to discontinuous quasilinear BVP’s. (English) Zbl 1071.35052 Appl. Anal. 82, No. 10, 1017-1028 (2003). Reviewer: Marlène Frigon (Montréal) MSC: 35J65 35R05 47H07 47H10 35J25 47N20 PDFBibTeX XMLCite \textit{S. Carl} and \textit{S. Heikkilä}, Appl. Anal. 82, No. 10, 1017--1028 (2003; Zbl 1071.35052) Full Text: DOI
Heikkilä, S.; Lakshmikantham, V. On mild solutions of first order discontinuous semilinear differential equations in Banach spaces. (English) Zbl 0832.34054 Appl. Anal. 56, No. 1-2, 131-146 (1995). Reviewer: P.Drábek (Plzeň) MSC: 34G20 47H07 35D05 PDFBibTeX XMLCite \textit{S. Heikkilä} and \textit{V. Lakshmikantham}, Appl. Anal. 56, No. 1--2, 131--146 (1995; Zbl 0832.34054) Full Text: DOI
Heikkilä, S.; Hu, S. On fixed points of multifunctions in ordered spaces. (English) Zbl 0839.54033 Appl. Anal. 51, No. 1-4, 115-127 (1993). MSC: 54H25 47H10 54C60 PDFBibTeX XMLCite \textit{S. Heikkilä} and \textit{S. Hu}, Appl. Anal. 51, No. 1--4, 115--127 (1993; Zbl 0839.54033) Full Text: DOI
Heikkilä, Seppo On extremal solutions of operator equations in ordered normed spaces. (English) Zbl 0821.47041 Appl. Anal. 44, No. 1-2, 77-97 (1992). MSC: 47H07 47H10 47J05 47J10 PDFBibTeX XMLCite \textit{S. Heikkilä}, Appl. Anal. 44, No. 1--2, 77--97 (1992; Zbl 0821.47041) Full Text: DOI
Heikkilä, Seppo On an elliptic boundary value problem with discontinuous nonlinearity. (English) Zbl 0726.35045 Appl. Anal. 37, No. 1-4, 183-189 (1990). Reviewer: J.Frehse (Bonn) MSC: 35J65 35R05 PDFBibTeX XMLCite \textit{S. Heikkilä}, Appl. Anal. 37, No. 1--4, 183--189 (1990; Zbl 0726.35045) Full Text: DOI
Heikkilä, Seppo On the method of iteratively generated chain approximations for equations in function spaces. (English) Zbl 0672.47041 Appl. Anal. 28, No. 3, 181-197 (1988). Reviewer: Ioan A.Rus MSC: 47H10 47J25 PDFBibTeX XMLCite \textit{S. Heikkilä}, Appl. Anal. 28, No. 3, 181--197 (1988; Zbl 0672.47041) Full Text: DOI
Heikkilä, Seppo A fixed point lemma with applications. (English) Zbl 0654.47040 Appl. Anal. 30, No. 1-3, 165-174 (1988). Reviewer: J.Appell MSC: 47H10 54H25 PDFBibTeX XMLCite \textit{S. Heikkilä}, Appl. Anal. 30, No. 1--3, 165--174 (1988; Zbl 0654.47040) Full Text: DOI
Heikkila, S. On the quasimonotonicity of linear differential systems. (English) Zbl 0438.34027 Appl. Anal. 10, 121-126 (1980). MSC: 34C11 35B35 34A34 PDFBibTeX XMLCite \textit{S. Heikkila}, Appl. Anal. 10, 121--126 (1980; Zbl 0438.34027) Full Text: DOI