Construction of a Class of Sharp Löwner Majorants for a Set of Symmetric Matrices

<div>The straight lines depict the border of the set <span class="nowrap"><svg height="16.4744pt" id="M492" style="vertical-align:-3.908299pt" version="1.1" viewbox="-0.0498162 -12.5661 23.9824 16.4744" width="23.9824pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M895 660C863 648 835 636 808 620C736 668 639 687 564 687C395 687 153 589 153 403C153 307 221 260 300 260C447 260 534 401 534 561H514C506 396 415 290 305 290C234 290 194 335 194 396C194 555 383 657 566 657C626 657 716 643 776 601C669 531 592 432 501 271C389 71 313 16 189 16C118 16 69 60 69 95H71C78 84 93 83 101 83C129 83 144 106 144 131C144 160 121 179 93 179C60 179 34 150 34 107C34 41 100 -15 207 -15C365 -15 509 76 621 311C626 300 647 292 668 292C675 292 701 294 717 298C752 278 763 243 763 203C763 140 734 78 685 49C666 38 647 34 624 34C596 34 574 55 574 82C574 127 623 171 679 176L675 199C586 184 537 132 537 67C537 32 567 -11 631 -11C672 -11 710 0 743 22C804 63 839 127 839 186C839 234 813 289 749 316V318C837 329 902 398 902 463C902 524 873 566 830 601C850 615 874 628 902 641L895 660ZM841 485C841 420 802 346 717 338C697 349 675 352 662 352C655 352 644 351 639 348C691 449 736 524 801 580C825 555 841 524 841 485Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,12.35,-6.049)"><path d="M309 -142C211 -61 151 99 151 271S210 601 309 683L288 710C141 611 75 451 75 272V271C75 90 141 -72 288 -169L309 -142Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,15.608,-6.049)"><path d="M389 0V32C297 38 291 46 291 118V635C234 613 175 595 109 583V556L161 554C203 552 207 547 207 497V118C207 46 201 38 110 32V0H389Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,20.04,-6.049)"><path d="M283 271C283 451 220 610 70 710L48 683C146 603 207 443 207 271S149 -59 48 -142L70 -169C220 -67 283 90 283 271Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,12.35,3.858)"><path d="M414 144C384 79 371 75 317 75H135L276 221C367 316 408 376 408 465C408 570 327 635 237 635C179 635 131 609 100 575L42 494L67 471C94 510 138 565 205 565C277 565 321 517 321 435C321 348 258 270 195 195C146 137 88 81 33 26V0H411C423 44 433 88 446 135L414 144Z"></path></g></svg>,</span> the curved line represents the border of the set <span class="nowrap"><svg height="16.4744pt" id="M493" style="vertical-align:-3.908299pt" version="1.1" viewbox="-0.0498162 -12.5661 23.9824 16.4744" width="23.9824pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M895 660C863 648 835 636 808 620C736 668 639 687 564 687C395 687 153 589 153 403C153 307 221 260 300 260C447 260 534 401 534 561H514C506 396 415 290 305 290C234 290 194 335 194 396C194 555 383 657 566 657C626 657 716 643 776 601C669 531 592 432 501 271C389 71 313 16 189 16C118 16 69 60 69 95H71C78 84 93 83 101 83C129 83 144 106 144 131C144 160 121 179 93 179C60 179 34 150 34 107C34 41 100 -15 207 -15C365 -15 509 76 621 311C626 300 647 292 668 292C675 292 701 294 717 298C752 278 763 243 763 203C763 140 734 78 685 49C666 38 647 34 624 34C596 34 574 55 574 82C574 127 623 171 679 176L675 199C586 184 537 132 537 67C537 32 567 -11 631 -11C672 -11 710 0 743 22C804 63 839 127 839 186C839 234 813 289 749 316V318C837 329 902 398 902 463C902 524 873 566 830 601C850 615 874 628 902 641L895 660ZM841 485C841 420 802 346 717 338C697 349 675 352 662 352C655 352 644 351 639 348C691 449 736 524 801 580C825 555 841 524 841 485Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,12.35,-6.049)"><path d="M309 -142C211 -61 151 99 151 271S210 601 309 683L288 710C141 611 75 451 75 272V271C75 90 141 -72 288 -169L309 -142Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,15.608,-6.049)"><path d="M414 144C384 79 371 75 317 75H135L276 221C367 316 408 376 408 465C408 570 327 635 237 635C179 635 131 609 100 575L42 494L67 471C94 510 138 565 205 565C277 565 321 517 321 435C321 348 258 270 195 195C146 137 88 81 33 26V0H411C423 44 433 88 446 135L414 144Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,20.04,-6.049)"><path d="M283 271C283 451 220 610 70 710L48 683C146 603 207 443 207 271S149 -59 48 -142L70 -169C220 -67 283 90 283 271Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,12.35,3.858)"><path d="M414 144C384 79 371 75 317 75H135L276 221C367 316 408 376 408 465C408 570 327 635 237 635C179 635 131 609 100 575L42 494L67 471C94 510 138 565 205 565C277 565 321 517 321 435C321 348 258 270 195 195C146 137 88 81 33 26V0H411C423 44 433 88 446 135L414 144Z"></path></g></svg>,</span> and the gray region illustrates the set <span class="nowrap"><svg height="15.7816pt" id="M494" style="vertical-align:-3.834pt" version="1.1" viewbox="-0.0498162 -11.9476 20.8037 15.7816" width="20.8037pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M895 660C863 648 835 636 808 620C736 668 639 687 564 687C395 687 153 589 153 403C153 307 221 260 300 260C447 260 534 401 534 561H514C506 396 415 290 305 290C234 290 194 335 194 396C194 555 383 657 566 657C626 657 716 643 776 601C669 531 592 432 501 271C389 71 313 16 189 16C118 16 69 60 69 95H71C78 84 93 83 101 83C129 83 144 106 144 131C144 160 121 179 93 179C60 179 34 150 34 107C34 41 100 -15 207 -15C365 -15 509 76 621 311C626 300 647 292 668 292C675 292 701 294 717 298C752 278 763 243 763 203C763 140 734 78 685 49C666 38 647 34 624 34C596 34 574 55 574 82C574 127 623 171 679 176L675 199C586 184 537 132 537 67C537 32 567 -11 631 -11C672 -11 710 0 743 22C804 63 839 127 839 186C839 234 813 289 749 316V318C837 329 902 398 902 463C902 524 873 566 830 601C850 615 874 628 902 641L895 660ZM841 485C841 420 802 346 717 338C697 349 675 352 662 352C655 352 644 351 639 348C691 449 736 524 801 580C825 555 841 524 841 485Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,12.35,-5.741)"><path d="M837 672C829 675 822 674 813 674C710 674 608 541 510 398C475 447 422 480 349 480C260 480 162 415 162 299C162 199 212 133 284 92C229 39 191 15 134 15C91 15 69 45 69 65H71C78 54 95 53 100 53C128 53 143 80 143 101C143 128 121 149 93 149C60 149 31 121 31 77C31 24 74 -15 138 -15C198 -15 255 22 311 79C360 56 416 43 473 39L455 0H552L569 42C612 49 661 63 693 87L684 103C657 88 617 76 581 69C677 301 753 477 846 658L837 672ZM772 638C701 530 628 379 559 227C558 279 547 330 526 371C609 494 688 609 771 638H772ZM536 199C536 191 536 184 535 176L486 67C430 71 380 84 335 105C395 173 451 257 507 344C527 301 536 251 536 199ZM492 372C431 277 369 183 310 119C245 158 203 217 203 301S275 447 349 447C416 447 461 417 492 372Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,12.35,3.784)"><path d="M414 144C384 79 371 75 317 75H135L276 221C367 316 408 376 408 465C408 570 327 635 237 635C179 635 131 609 100 575L42 494L67 471C94 510 138 565 205 565C277 565 321 517 321 435C321 348 258 270 195 195C146 137 88 81 33 26V0H411C423 44 433 88 446 135L414 144Z"></path></g></svg>.</span></div>

Journal of Applied Mathematics

fig6

Figure 6

Figure 6: Construction of a Class of Sharp Löwner Majorants for a Set of Symmetric Matrices 