An Analysis of the Theta-Method for Pantograph-Type Delay Differential Equations

<div>Numerical simulations of model (<a href="https://static-preview.hindawi.com/articles/complexity/volume-2022/8961352/figures/#EEq36">36</a>) with <svg height="9.49473pt" id="M166" style="vertical-align:-0.2063999pt" version="1.1" viewbox="-0.0498162 -9.28833 37.2841 9.49473" width="37.2841pt" 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="M501 444C501 643 409 712 321 712C208 712 108 618 108 502C108 412 172 331 293 331C337 331 394 359 420 378C397 154 341 41 258 41C209 41 178 76 178 161C178 232 171 299 114 299C76 299 38 272 23 257L29 232C42 236 54 239 66 239C91 239 106 221 102 149C95 20 158 -12 219 -12C264 -12 314 10 353 47C461 150 501 295 501 444ZM423 443C423 433 422 422 421 412C401 396 370 385 335 385C245 385 180 444 180 537C180 609 212 671 286 671C349 671 423 595 423 443Z"></path></g><g transform="matrix(.013,0,0,-0.013,10.367,0)"><path d="M535 323V373H52V323H535ZM535 138V188H52V138H535Z"></path></g><g transform="matrix(.013,0,0,-0.013,21.63,0)"><path d="M241 635C89 635 35 457 35 312C35 153 89 -12 240 -12C390 -12 443 166 443 312C443 466 390 635 241 635ZM238 602C329 602 354 454 354 312C354 172 330 22 240 22C152 22 124 173 124 313S148 602 238 602Z"></path></g><g transform="matrix(.013,0,0,-0.013,27.87,0)"><path d="M113 -12C146 -12 170 11 170 46C170 78 146 103 114 103S58 78 58 46C58 11 82 -12 113 -12Z"></path></g><g transform="matrix(.013,0,0,-0.013,30.834,0)"><path d="M241 635C89 635 35 457 35 312C35 153 89 -12 240 -12C390 -12 443 166 443 312C443 466 390 635 241 635ZM238 602C329 602 354 454 354 312C354 172 330 22 240 22C152 22 124 173 124 313S148 602 238 602Z"></path></g></svg> (a) and <svg height="9.49473pt" id="M167" style="vertical-align:-0.2063999pt" version="1.1" viewbox="-0.0498162 -9.28833 37.2841 9.49473" width="37.2841pt" 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="M501 444C501 643 409 712 321 712C208 712 108 618 108 502C108 412 172 331 293 331C337 331 394 359 420 378C397 154 341 41 258 41C209 41 178 76 178 161C178 232 171 299 114 299C76 299 38 272 23 257L29 232C42 236 54 239 66 239C91 239 106 221 102 149C95 20 158 -12 219 -12C264 -12 314 10 353 47C461 150 501 295 501 444ZM423 443C423 433 422 422 421 412C401 396 370 385 335 385C245 385 180 444 180 537C180 609 212 671 286 671C349 671 423 595 423 443Z"></path></g><g transform="matrix(.013,0,0,-0.013,10.367,0)"><path d="M535 323V373H52V323H535ZM535 138V188H52V138H535Z"></path></g><g transform="matrix(.013,0,0,-0.013,21.63,0)"><path d="M241 635C89 635 35 457 35 312C35 153 89 -12 240 -12C390 -12 443 166 443 312C443 466 390 635 241 635ZM238 602C329 602 354 454 354 312C354 172 330 22 240 22C152 22 124 173 124 313S148 602 238 602Z"></path></g><g transform="matrix(.013,0,0,-0.013,27.87,0)"><path d="M113 -12C146 -12 170 11 170 46C170 78 146 103 114 103S58 78 58 46C58 11 82 -12 113 -12Z"></path></g><g transform="matrix(.013,0,0,-0.013,30.834,0)"><path d="M412 140C382 77 369 73 315 73H129L270 222C362 320 402 379 402 466C402 571 322 635 234 635C177 635 130 609 99 576L42 495L64 475C90 514 133 568 201 568C274 568 318 519 318 435C318 349 255 267 193 193C144 135 87 78 32 23V0H405C417 45 427 89 440 131L412 140Z"></path></g></svg> (b), when <span class="nowrap"><svg height="9.49473pt" id="M168" style="vertical-align:-0.2063999pt" version="1.1" viewbox="-0.0498162 -9.28833 37.7278 9.49473" width="37.7278pt" 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="M529 97L508 118C475 75 449 58 438 58C428 58 421 66 415 104C393 234 374 403 364 496C345 670 307 712 254 712C220 712 174 691 153 669L161 645C176 653 194 658 206 658C237 658 261 640 278 562C287 522 290 483 293 434C223 269 110 105 23 9L32 -12C59 -6 85 0 108 7C152 64 251 252 300 366C307 297 315 221 337 82C346 24 363 -12 393 -12C425 -12 475 13 529 97Z"></path></g><g transform="matrix(.013,0,0,-0.013,10.806,0)"><path d="M535 323V373H52V323H535ZM535 138V188H52V138H535Z"></path></g><g transform="matrix(.013,0,0,-0.013,22.068,0)"><path d="M241 635C89 635 35 457 35 312C35 153 89 -12 240 -12C390 -12 443 166 443 312C443 466 390 635 241 635ZM238 602C329 602 354 454 354 312C354 172 330 22 240 22C152 22 124 173 124 313S148 602 238 602Z"></path></g><g transform="matrix(.013,0,0,-0.013,28.308,0)"><path d="M113 -12C146 -12 170 11 170 46C170 78 146 103 114 103S58 78 58 46C58 11 82 -12 113 -12Z"></path></g><g transform="matrix(.013,0,0,-0.013,31.272,0)"><path d="M244 635C114 635 38 519 38 422C38 317 111 240 217 240C236 240 255 244 277 256L345 292C311 140 203 39 59 15L64 -15C89 -15 150 -5 204 17C339 72 440 202 440 386C440 521 368 635 244 635ZM228 602C326 602 352 479 352 390C352 370 351 347 348 324C327 308 293 296 258 296C174 296 124 369 124 458C124 517 152 602 228 602Z"></path></g></svg>.</span></div>

Complexity

fig2

Figure 2

Figure 2: An Analysis of the Theta-Method for Pantograph-Type Delay Differential Equations 