Rapperswil-Jona is a municipality in the Wahlkreis of See-Gaster in the canton of St. Gallen in Switzerland. Besides Rapperswil and Jona, which were separate municipalities until 2006, the municipality includes Bollingen, Curtiberg, Kempraten-Lenggis and Wurmsbach; the official language of Rapperswil is German, but the main spoken language is the local variant of the Alemannic Swiss German dialect. On January 1, 2007, the municipalities of Rapperswil and Jona merged to form a new political entity. After the merger Rapperswil-Jona had a population of 25,777; this makes it the second largest town in the canton after the capital St. Gallen itself. On 31 December 2018 the population was 26,999. Rapperswil-Jona is one of the most significant traffic junctions in the region, Rapperswil railway station is a nodal point for the Swiss Federal Railways, Südostbahn and S-Bahn Zürich lines. Zürichsee-Schifffahrtsgesellschaft operates passenger vessels on the Lake Zürich, connecting surrounding towns between Zürich-Bürkliplatz and Rapperswil.

The Seedamm, a dam across Lake Zürich, links Rapperswil with Hurden on the other side of the lake. This connection has been part of old pilgrimage routes. From early centuries, a wooden footbridge led across Lake Zürich. At a stage, the bridge was replaced by a stone dam. In 2001, a new wooden footbridge was opened alongside the dam for the first 840 meters of the crossing, it was built in the same place as the original bridge and links Rapperswil with the nearby bridge chapel built in 1551. The main sights are concentrated in the centre of Rapperswil and can be seen while strolling through the medieval alleys; the main sights of Rapperswil are its roses, the castle, the reconstructed wooden bridge to Hurden with its bridge chapel, a Capuchin monastery. There are a number of churches and the nearby Wurmsbach Abbey. In the surroundings of the town there are a number of churches. St. John's Church in Rapperswil was built around 1220 and became Rapperswil's parish church in 1253, the Chapel St. Ursula in the village of Kempraten was built around 885.

The St. Dionysius Chapel, dedicated to Denis, the first bishop of Paris, was reconstructed in 1493 and attracts pilgrims; the nunnery at Wurmsbach was established in 1259 and today houses an institute for girls, St. Martin Busskirch is the former parish church of Rapperswil. Bollingen is known for the "Tower" built there by Carl Jung. Kempraten is one of the most important archeological sites in the canton of St. Gallen and is located at the eastern parts of the upper Lake Zürich. Jona river is flowing through the municipality in the upper Lake Zürich. In 2006 Rapperswill-Jona hosted the World Orienteering Championships. Settlements in the region of Rapperswil date back at least 5000 years. Atop the Lindenhof hill overlooking a former small village, Rapperswil Castle was built around 1220 by the Counts of Rapperswil and is first mentioned in 1229; the town was founded when the nobility of Rapperswil moved from Altendorf across the lake to Rapperswil. The town was soon acquired by the Habsburg family who, in 1358/60, built the wooden bridge across the upper Lake Zürich.

The town bought itself free, ending Old Zürich War made an alliance with the Swiss Confederation. Because of its strategic location along important infrastructure the town grew rich because of flourishing trade; this allowed a certain degree of freedom, ended with the formation of Swiss cantons by Napoleon. Rapperswil was at first part of the Helvetic canton of Linth. After 1803's Act of Mediation, it joined the canton of St. Gallen; the locational advantage of the place attracted the national Circus Knie who built its headquarters in Rapperswil in 1919. The circus is now responsible for the Knie's Kinderzoo and the Circus Museum. Rapperswil-Jona has an area, as of 2006, of 22.2 square kilometers. Of this area, 37.4% is used for agricultural purposes, while 30.6% is forested. Of the rest of the land, 28.6% is settled and the remainder is non-productive. The municipality is located in the See-Gaster Wahlkreis and was formed from the merger of Rapperswil and Jona. Most of the population speaks German, with Italian being second most common and Serbo-Croatian being third.

In the 2007 federal election the most popular party was the SVP. The next three most popular parties were the CVP, the SP and the FDP. In Rapperswil-Jona about 74.6% of the population have completed either non-mandatory upper secondary education or additional higher education. As of 2007, Rapperswil-Jona had an unemployment rate of 1.84%. As of 2005, there were 183 people employed in the primary economic sector and about 56 businesses involved in this sector. 3,898 people are employed in the secondary sector and there are 231 businesses in this sector. 8,340 people are employed in the tertiary sector, with 1,077 businesses in this sector. Among other companies, LafargeHolcim, Obersee Nachrichten and Radio Zürisee are situated in Rapperswil-Jona; the municipality of Rapperswil-Jona is served by four railway stations, of which the main one is Rapperswil railway station. This is served by lines S5, S7, S15 and S40 of the Zürich S-Bahn, the first three of which provide frequent and fast links to the city of Zürich.

It is a calling point of the Voralpen Express, running hourly between Lucerne and St. Gallen, the terminus of an hourly regional train that operates south-east t

Grundlagen der Mathematik is a two-volume work by David Hilbert and Paul Bernays. Published in 1934 and 1939, it presents fundamental mathematical ideas and introduced second-order arithmetic. 1934/1939 First German edition, Springer 1944 Reprint of first edition by J. W. Edwards, Ann Arbor, Michigan. 1968/1970 Second revised German edition, Springer 1979/1982 Russian translation of 1968/1970, Nauka Publ. Moscow 2001/2003 French translation, L’Harmattan, Paris 2011/2013 English translation of 1968 and 1934, bilingual with German facsimile on the left-hand sides; the Hilbert Bernays Project is producing an English translation. Hilbert–Bernays paradox Sieg, Wilfried. David Hilbert and Paul Bernays, Grundlagen der Mathematik", in Grattan-Guinness, Landmark writings in western mathematics 1640--1940, Elsevier B. V. Amsterdam, pp. 981–99, doi:10.1016/B978-044450871-3/50158-3, ISBN 978-0-444-50871-3, MR 2169816 Hilbert, David. I, Die Grundlehren der mathematischen Wissenschaften, 40, New York: Springer-Verlag, ISBN 978-3-540-04134-4, JFM 60.0017.02, MR 0237246, archived from the original on 2011-05-17 Hilbert, David.

II, Die Grundlehren der mathematischen Wissenschaften, 50, New York: Springer-Verlag, ISBN 978-3-540-05110-7, JFM 65.0021.02, MR 0272596, archived from the original on 2011-05-17 Hilbert, David. I, Die Grundlehren der mathematischen Wissenschaften, 40, New York: Springer-Verlag, ISBN 978-3642868955, MR 0237246 Hilbert, D.. II, Die Grundlehren der mathematischen Wissenschaften, 50, Berlin-New York: Springer-Verlag, ISBN 978-3642868979, MR 0272596 Hilbert, David. London: College Publications, ISBN 978-1-84890-075-2 Hilbert Bernays Project which aims to produce an English translation of Grundlagen der Mathematik

The Basilica of San Savino is an ancient Roman Catholic basilica in the city of Piacenza in the Province of Piacenza, Italy. A church at the site was consecrated in 1107 to Saint Sabinus of Piacenza, second bishop of the city, it was built by bishop Sigifredo. The crypt of the church has 12th-century mosaics depicting the zodiac signs on a marine background; the presbytery has a contemporary mosaic showing a depiction of Christ. In the 1500s, the church became property of the Hieronymite order. In the 18th century, the church interior was decorated in a Rococo style, hiding much of the original Romanesque details. In 1721, the present facade was built. Among the works of art in the church is a wooden crucifix and frescos from the 12th century and a 15th-century fresco in the presbytery depicting an Enthroned Madonna and child. In 1819, the hospice for "orphans and the exposed" with 60 children was moved to the Girolamini monastery attached to San Savino; the hospice had been founded in 1573 by the bishop, run by the Somaschi order of Clerics Regular.

They were affiliated with the parish church of San Stefano. The orphanage had been housed in the Convent of Sant'Anna